Fee comparisons rank a completed sale. Sellers do not live in that world. A channel that lets you list higher can still lose once you count the share of orders that come back, the return postage you pay, and the units that cannot be sold again.
Same source cost on both channels: $14 to buy, $5 outbound postage, $1 to pack. eBay lists at $48 plus $6 shipping. Amazon lists at $54 plus the same $6 — a realistic Prime premium, not a different product.
Using illustrative US rates — eBay 13.6% + $0.40, Amazon 15% referral plus $39.99/month spread over 100 orders — the completed sales look like this:
| Line | eBay at $48 | Amazon at $54 |
|---|---|---|
| Order total | $54.00 | $60.00 |
| Percentage and plan fees | −$7.74 | −$9.40 |
| Item, postage, packaging | −$20.00 | −$20.00 |
| You keep on a completed sale | $26.26 | $30.60 |
List $6 higher on Amazon and the completed sale leaves about $4 more. That is the ranking a fee-only calculator reports.
Now apply illustrative return assumptions a seller can replace with their own report: eBay 8% of orders come back, Amazon 18%. Return postage is $6 on eBay and $7 on Amazon. Nine in ten eBay returns can be listed again; four in five Amazon returns can. Percentage fees are refunded; the Amazon plan share is not.
| Line | eBay | Amazon |
|---|---|---|
| Cash on a returned order | −$13.40 | −$16.20 |
| Return rate | 8% | 18% |
| Expected keep | $23.08 | $22.18 |
| Return drag versus a perfect sale | $3.17 | $8.42 |
Amazon still looks better on every completed sale. In the mix a seller actually lives in, eBay leaves $0.90 more. The $4 completed-sale gap was more than eaten by the extra returns.
None of those rates is a published marketplace schedule. Replace them with the numbers on your own return report — apparel often comes back more often than hard goods, and “still sellable” is the assumption that moves the ranking most after the return rate itself.
Run these numbers on your own item →
Yes. In the worked example Amazon keeps $30.60 on a completed sale against eBay's $26.26, but at an 8% eBay return rate and an 18% Amazon return rate the expected keep is $23.08 on eBay and $22.18 on Amazon. The $4 completed-sale lead is more than eaten by the extra returns.
You refund the buyer, so there is no sale revenue, and outbound postage, packaging, and fulfilment are already spent. You pay return postage unless the buyer does. A share of percentage and fixed payment fees may come back, but listing fees and the monthly-plan share do not. Units that cannot be sold again cost you the item, and units that can are inventory again rather than a second purchase.