SellculateSelling through a marketplace is a trade: you get the audience, the platform gets a slice of every sale. The trade is usually worth it — but only if your price is built with the slice in mind. Most disappointed sellers didn't pick a bad product; they priced a good one as if the payout would equal the price.
The anatomy of a fee stack
Details differ by platform and change over time, but nearly every marketplace sale passes through the same categories of deduction:
- Platform commission — a percentage of the sale, and on many platforms a percentage of the total the buyer pays, including shipping and sometimes tax.
- Payment processing — typically a percentage plus a flat amount per transaction. The flat part matters far more than it looks on cheap items.
- Listing or insertion fees — small per-listing charges that exist on some platforms and are easy to forget because they're billed separately from the sale.
- Shipping you absorb — "free shipping" is a price cut wearing a marketing hat. If you pay the label, it belongs in the calculation as a cost.
- Packaging and fixed costs — boxes, mailers, tape, labels, filler. Small per unit, relentless in aggregate.
- Tax or VAT — depending on your jurisdiction and setup, tax may be included in your displayed price (and thus not yours to keep) or added on top. Getting inclusive-vs-exclusive wrong skews every number downstream.
One structural point is worth underlining: percentage fees scale with your price, flat fees don't. That's why the same fee schedule can be mildly annoying on a $60 item and brutal on an $8 one.
A worked example
Say you make a product for $9.00 in materials and sell it for $35.00 with free shipping. The numbers below are illustrative — every platform's real schedule is different and changes; always verify current rates.
| Line | Amount |
|---|---|
| Selling price | $35.00 |
| Product cost | −$9.00 |
| Shipping label (absorbed) | −$4.75 |
| Packaging | −$0.60 |
| Platform commission (6.5%) | −$2.28 |
| Payment processing (3% + $0.25) | −$1.30 |
| Listing fee | −$0.20 |
| Net profit | $16.87 |
The naive read of this product — price minus materials — says profit is $26.00 and margin is a glorious 74.3%. The real margin, after the stack, is 16.87 ÷ 35.00 = 48.2%. Still healthy! But that's a 26-point gap between the margin you'd guess and the margin you'd get, and every decision made from the naive number — how much discount you can afford, whether a wholesale order makes sense, what your hourly rate works out to — inherits the error.
Now add a discount
Run the same product through a 15%-off sale. The new price is $29.75. The percentage fees shrink with the price (commission drops to about $1.93, processing to $1.14), but your product cost, shipping, packaging and listing fee don't move. Net profit lands around $12.13, a margin of 40.8%.
Read that again from the buyer's side versus yours: a 15% discount to the customer became a 28% cut to your profit. That asymmetry — discounts come off the top, but most costs are fixed — is the single most important thing to understand before running a sale. It's also why comparing base and discounted scenarios side by side, before committing, beats finding out on payout day.
Pricing so the margin survives
The forward direction (pick a price, compute the margin) is fine for checking an existing listing. For new products, work backwards from the margin you want to keep:
- Total your per-unit costs — product, inbound freight share, packaging, absorbed shipping, listing fee.
- Total your percentage fees — platform commission plus processor percentage, as one combined rate.
- Solve for price:
price = (unit costs + flat fees) ÷ (1 − target margin − fee rate). The full derivation, with worked numbers, is in our reverse margin guide. - Sanity-check against the market. If the solved price is above what buyers will pay, the answer isn't to shave the math — it's a cheaper cost base, a different platform mix, or a different product.
Two habits keep the whole system honest. First, keep a fee profile per platform you sell on — commission, processor rate, flat fees, listing fee — and update it when the platforms update theirs, because they do. Second, recompute your standard products a couple of times a year; fee changes, postage increases and supplier creep all arrive quietly. If you also source inventory, the same fee-stack thinking applies in reverse to what you can afford to pay — see the hidden-costs guide for the sourcing side, and make sure the percentage you're targeting is genuinely a margin, not a markup (the difference matters).
Where Sellculate fits in
Sellculate is built around exactly this cost stack: shipping, packaging and fixed costs, platform fees, payment processor fees, listing fees, tax or VAT, discounts and quantity, all in one calculation. Editable fee profiles let you keep one setup per marketplace and processor — the built-in templates are starting points only; always verify current rates. Scenario compare shows base vs discounted side by side, and saved products mean your standard items are one tap from a re-check. Local-first on Android, with no account system and no analytics SDK.
Fee figures in this guide are illustrative examples, not any platform's actual schedule. This is general pricing information, not tax, legal, or financial advice.