Questions sellers ask.

Amazon (US, UK, Germany, and 7 additional EU marketplaces), eBay (US, UK, and 9 additional marketplaces), Walmart (US), and Shopify. 26 marketplace fee structures in total — each extracted independently from its own published documentation.

No. FineMargins computes from published platform data — fee schedules, rate cards, programme pages — not your account's transaction history. You enter your product details. We compute the fees. This is a computation platform, not an account integration.

No. FineMargins provides access to a computation platform and structured platform data. Every number comes from a published source, verified and dated. We compute what the platform charges and surface which costs have published alternatives. We don't recommend, advise, or optimise. You see the numbers. You make the decision.

Every number links to the published source page. Click through. Read the page. Check the rate. The platform extracts from published rate cards — not platform APIs, not estimates, not AI-generated approximations. If the number on Amazon Seller Central says $3.95, the platform says $3.95. If it changes, the staleness monitor flags it. If you find a number that doesn't match the published source, tell us — we'll fix it and show you the correction. That's the transparency guarantee: every number verifiable, every source dated. The database contains 8,874 fee configurations extracted from platform documentation.

September 2026. Sign up for early access and you'll be notified first.

You're right — it IS all on Seller Central. Across 47 different pages. The fuel surcharge is on a different page from the rate card. The DST is on another page. The SIPP penalty is on a programme page. The storage surcharges are somewhere else. You can read all 47. Or the platform can check all 2,021 configurations against your product in seconds and tell you which ones apply. The information is public. The assembly isn't. That gap is worth $1,300 to $5,800/year on one product.

The free Margin Check lets you try the platform on one product before you pay anything. But the full analytical platform — payment chain mapping, cost alternatives, cascade modelling, change monitoring — costs real compute and real data maintenance. We'd rather build a tool worth paying for than a free tool funded by ads or your data.

Scale, not capability. Every paid tier gets the full analytical platform. Starter is one platform and ten products. Growth adds cross-platform comparison across three platforms and twenty-five products. Portfolio adds growth modelling, action sequencing, and expansion analysis across six platforms and seventy-five products. The question is how many platforms you sell on and how many products you need to track.

Yes — at any time. Upgrades take effect immediately. Downgrades take effect at the next billing cycle. Your data is always yours.

Your analyses remain accessible for 90 days after cancellation. Your data export is always available. After 90 days, we archive your data — but if you come back within 24 months, we restore everything.

The weight cliff on a $25 product is $0.26/unit. At 100 units/month — 1,200/year — that's $312. The fuel surcharge is $0.14/unit — $168/year at 100/month. The SIPP discount is $0.04/unit — $48/year. Add the price band insight, the programme eligibility, the cross-platform comparison — and the total for a 100-unit/month seller is still hundreds of dollars. Small margins compound. The sellers who can least afford to lose $0.26/unit are the ones selling 100 units/month, not 10,000.

$10,386 is 3.0% of his revenue. The SIPP enrollment alone is $2,448/year with zero cost to implement. The fuel surcharge model fix costs nothing — it's an hour of work that corrects every future margin calculation. These aren't volume-dependent savings that only matter at scale. They're structural — the same percentage error whether he sells 100 units or 100,000.

On one product. How many do you sell? The platform checks every SKU independently. SIPP applies to every FBA product you haven't enrolled. The fuel surcharge applies to every unit you ship. The size tier check applies to every product in your catalogue. A seller with 30 SKUs and $500K in revenue typically has $8,000 to $15,000 across the portfolio. And one of those products might be losing money after all 24 fee lines — you just don't know which one because you're tracking 3 of them.

Exactly. The platform runs the analysis on every product in your catalogue — and the insights multiply. One product near a weight cliff. Another near a price band threshold. A third eligible for a programme you've never applied for. A fourth that's losing money after the full waterfall and you didn't know because your spreadsheet only tracks two fee lines. Twenty products means twenty sets of thresholds, twenty sets of programme eligibility, twenty break-even ACoS calculations. The platform does all of them.

The Revenue Calculator shows referral fee and FBA fee. For the Running Shirt, it shows 15% referral ($5.25) and non-apparel FBA ($3.95). Both wrong. The actual rate is 17% ($5.95) on a different referral schedule, and $4.50 on the apparel FBA schedule. Plus a 3.5% fuel surcharge on a separate page. The Revenue Calculator doesn't know about the marginal rate structure, the apparel schedule, or the fuel surcharge. Alex's model is $1.41/unit wrong on one product. That's $16,920/year at his volume on just the Running Shirt — and the error propagates to every pricing, advertising, and profitability decision he makes using those numbers.

His Yoga Mat is losing money on every sale at realistic ad spend. Break-even ACoS is 14.9%. If he's running even moderate PPC on a product in Sports and Outdoors, he's likely above that. "Fine" means he hasn't run the full waterfall. The platform does — and it shows which products are genuinely profitable after all 24 cost lines, not just the ones that look good after 2.

A seller shared his full numbers publicly — 370 units, 38% margin. Every line itemised. Real number? About 16%. The 22-point gap wasn't PPC. It was fee lines he wasn't tracking. And here's why that matters for your PPC: your break-even ACoS is calculated from your margin. If your margin is 22 points lower than you think, campaigns that look profitable might not be. You're bidding against a number that's wrong. The fee problem IS the PPC problem — you just can't see it yet.

The referral fee is fixed. 15%, every seller, no alternative. You're right. But 184 other cost lines have alternatives. SIPP is free to enrol — $600/year. Inbound placement is a setting you picked without knowing it had a cost — $1,600 to $3,200/year. The size tier boundary is a packaging decision — $5,200/year. You need to know the fixed costs to get the real margin number. You need to know the changeable costs because that's where the money is. The platform separates them so you stop guessing which is which.

Fair. That's why the platform doesn't just show the saving — it models the payback. Retooling costs $2,000 and takes 6 weeks? Saving is $5,200/year? Payback: 20 weeks. Net year one: $3,200. After that, pure margin. But some products aren't worth the fight. The platform tells you which ones are. And for the ones that aren't, it moves to the next lever. There are 184. SIPP costs nothing to enrol. Inbound placement is one setting change. Not every lever requires a battle with Seller Support.

Three things changed in 2026. The fuel surcharge was April — not January. The SIPP flip was January but buried in a programme update. MCF Preferred Pricing was mid-year. The changes don't arrive in one announcement. They arrive across different pages, different dates, different marketplaces. January is the one you notice. The others accumulate in the background. The platform monitors 1,236 source URLs. When a rate changes, it computes the impact on YOUR products before it hits your bank statement.

Amazon's email said "an average increase of $0.08 per unit." On this product, the increase was $0.25 — three times the announced average. And the fuel surcharge wasn't in the email. It was announced separately, effective April, on a different page. Two changes, two announcements, two dates. The email gives you the headline. The platform gives you the per-unit impact on each of your products.

Correct — the penalty is Bulky only. But the SIPP discount applies to your Small standard products too. $0.04–$0.07/unit, free certification. On 10,000 units: $400–$700/year. And if you ever add a Bulky product to your catalogue, the penalty is waiting: $1.51–$4.04/unit from day one. The platform checks certification status on every product — not just the ones where the penalty applies.

It's a Final Value Fee (12.7% for Cell Phone Accessories), PLUS a per-order fee ($0.40), PLUS a store subscription ($21.95/month), PLUS Promoted Listings if he uses them (seller-set percentage), with payment processing bundled inside the FVF. That's at least four cost components, not one percentage. And the FVF rate varies by category — 9.35% for Consumer Electronics vs 12.7% for Cell Phone Accessories vs 14.35% for Media. "Just a percentage" undersells the complexity and hides the per-order fee that most sellers forget.

At 100 units/month in FVF savings, the Basic store breakeven is $21.95/month — 100 × $0.22 = $22/month. You're at breakeven. But that's only the FVF saving. How many active LISTINGS do you have? If you have 300 active listings with no store, you're paying $0.35 × 300 = $105/month in insertion fees. A Basic store costs $21.95/month and gives you 1,000 free listings. The insertion fee saving alone is $83/month. You evaluated the subscription on one cost line and missed the other two. That's what the platform checks.

It is — today. The Below Standard threshold is evaluated on a rolling basis. A bad batch of returns, a shipping delay during peak season, a spike in "item not as described" claims — any of these can push metrics below the threshold. The penalty doesn't appear on your fee page until it's already being charged. The platform monitors your metrics against the thresholds and flags when you're trending toward a penalty — before the +6% hits. Because once it hits, on a $25 product at 10,000 units, it's $15,000/year. You want to know that's coming, not discover it on your invoice.

eBay does change features and policies — sometimes without notice. That's the point of monitoring 1,236 source URLs across all platforms. When eBay updates a fee page, the platform detects the change and recomputes the impact on your products. You don't have to check the fee page every week. The platform checks it for you. And unlike an in-platform feature that can be removed by a feature flag, the computation is ours — built on the published rate cards, not on eBay's interface.

Because $1.03 is the best-case number — standard domestic cards, Shopify Payments, US-only. Your actual cost depends on your card mix, your processor, and whether you sell internationally. At 20% Amex + 15% international cards, you're paying $1.16 — $1,300/year more than the headline rate. With a third-party processor: $1.53 — $5,000/year more. And if you sell in multiple currencies, conversion fees add another 1.5–3.0%. The $1.03 is the floor, not the number.

That's the rate for standard domestic cards on your plan. It's not the rate for Amex (3.5%), international cards (3.9%), PayPal Wallet (3.49% + $0.49), or Klarna (4.99%). Your effective rate is the weighted average across ALL your payment methods. A seller who's never analysed their payment mix is pricing, budgeting, and making margin decisions against a number that's wrong. The platform computes your actual blended rate from your real mix.

Your CAC is real and probably your biggest cost. But here's the thing: your break-even CAC is calculated from your margin. If your processing cost is $1.16 instead of $1.03 and your fulfilment is $4.50 instead of $3.00, your actual margin is $1.63/unit lower than you think. That changes your maximum profitable CAC from $5.50 to $3.87. You might be acquiring customers at a CAC you think is profitable — and it's not. The processing cost problem IS the CAC problem. Wrong margin means wrong CAC ceiling.

Your choice — and on Basic, it costs you $0.50 per transaction in additional Shopify fees on top of whatever Stripe charges. $5,000/year at 10,000 transactions. If Stripe offers something Shopify Payments genuinely can't match for your business, that $5,000 might be justified. But most sellers on Basic using a third-party processor are paying for a preference, not a requirement. The platform shows the exact cost difference so you can decide with a number, not a feeling.

True. But the question isn't "does Walmart have less traffic than Amazon?" — it's "does the traffic it does have, at $4.75/unit lower cost, produce a higher margin per unit?" If Marcus sells 100 Yoga Mats/month on Walmart instead of Amazon, he keeps $4.76 more per unit — $5,712/year on that product alone. Even at HALF the volume he does on Amazon, the per-unit economics can make Walmart more profitable. The platform shows both sides: the fee saving AND the volume trade-off. He decides.

He's already on both platforms. He listed on Walmart for the reach. The question is whether he's selling the RIGHT products on each platform. Right now he's selling the same mix on both. The platform shows which products are cheaper on which platform — and by how much. Yoga Mat is $4.75/unit cheaper on Walmart. Vitamin D is $0.90 cheaper. These aren't small differences. And the management overhead of shifting volume isn't "managing two platforms" — it's adjusting inventory allocation on platforms he already manages.

They do. Which is why it's Priority 1. The discount is 20-30% off referral fees for a qualifying period. Once it expires, the standard Walmart referral rates apply — which are identical to Amazon for most categories. But the fulfilment gap ($2.92/unit on Yoga Mat), the packaging gap ($1.51/unit), and the fuel surcharge gap ($0.32/unit) are permanent structural differences. The New-Seller Savings are a bonus. The platform comparison is the long-term story.

It's confusing because the weight band structures aren't parallel. Walmart uses 7 pound-based bands. Amazon uses 8+ ounce-based bands per size tier with price-band multipliers. Comparing them in a spreadsheet means building two different lookup tables and running every product through both. The platform does this automatically — at your exact weight, not a rounded approximation. And it shows the specific weight where the cheaper platform flips. On this product, Walmart wins. On a 1.5 lb product, check.

You track the fees each platform shows you. Amazon UK shows referral + FBA. Amazon US shows the same. eBay shows FVF. But Amazon doesn't show you the fuel surcharge on the same page as the FBA rate. Amazon US doesn't show you the ACCS until it's on your settlement statement. The DST is on a page most UK sellers have never visited. And your eBay model double-counts payment processing because eBay bundles it into FVF and your spreadsheet doesn't know that. You're tracking what each platform puts in front of you. The platform tracks what each platform publishes across all their pages — and cross-references them.

ACCS alone is 1.5% of $120K = $1,800/year. That's money leaving your account on every disbursement. Fuel surcharge at 3.5% on your US FBA fees is another $504/year. These aren't percentages of your total revenue — they're absolute dollars deducted from your actual payouts. On a margin of 15-20%, $2,304 in untracked costs could be the difference between a profitable US operation and a break-even one.

That's the point. The platform does it. It holds the fee structures for all three platforms, cross-references them against your products, and surfaces findings you'd never find manually because no human has time to read 14 separate fee pages across three platforms in two countries and compute the interactions. You manage the business. The platform manages the numbers.

They don't matter — today. But if you're evaluating expansion, the fees on the destination marketplace are the first thing to check. Amazon FR fulfilment costs 57% more than Amazon DE for the same product. Amazon IE charges 0% DST. eBay Spain charges 29% less commission than eBay US. These differences change the expansion economics — and the platform holds them before you commit capital to a new marketplace.

The fees are already in the platform. All 26 marketplace structures. All extracted. Before you expand, you can see what every fee line costs on the destination marketplace — at your product's exact weight, dimensions, and category. Not after you've listed, shipped inventory, and discovered the rates are different. Before you commit. That's the point.

You don't care — today. But the platform holds fee rules for 26 marketplaces independently. If you expand to Amazon UK, the fuel surcharge is 1.5%, not 3.5%. That's a 2 percentage point difference on your fulfilment cost — in your favour. If you expand to Amazon DE, MCF Preferred Pricing may arrive and the platform will model it before it's announced. The fee structures across marketplaces are different — and knowing the differences before you expand means better decisions, not surprises.

There's no universal answer. It depends on your product's weight, category, your fulfilment costs, and your customer acquisition costs. On a $29.99 water bottle, Amazon charges $9.31 (including fulfilment) and eBay charges $4.21 (not including fulfilment). Strip fulfilment from Amazon and the marketplace access gap is $0.29. On a 4.5 lb Yoga Mat, the Amazon-to-Walmart gap widens to $4.75/unit — $11,400/year. The analysis runs every product across every platform and flags where the comparison flips.

Amazon vs eBay → · Amazon vs Walmart → · Amazon vs Shopify →

Not directly — they're different business models. Amazon's fees include fulfilment, customer traffic, and returns. Shopify's fees are payment processing only. The analysis maps what each side charges and flags exactly what inputs you need to provide on the Shopify side (fulfilment cost, customer acquisition cost) to make the comparison real. Amazon vs Shopify →

Significantly. Amazon US uses ounce-based weight bands. Amazon UK uses gram-based tiers. Fulfilment rates, fuel surcharges, and subscription costs all differ. And if you're established outside the US, Digital Services Tax adds 2–3% on every marketplace. A UK seller on Amazon US pays $8,760/year more than a US seller on the same product at 12,000 units. Amazon UK vs US vs EU →