Seller resource library
Marketplace fee and profit guides
Understand what Amazon, Etsy, and eBay charge, why apparently profitable products lose money, and how to compare channels using the same cost assumptions.
Start with a selling decision
Amazon vs Etsy vs eBay
Run one product through all three fee models and compare estimated unit profit.
Compare marketplaces → MethodologyHow we calculate marketplace fees
Review fee bases, rounding, assumptions, exclusions, and the official sources behind each model.
Read the method → Pricing fundamentalsWhy cheap items lose margin
See how fixed order, fulfillment, postage, and packaging costs squeeze low-price products.
Protect your margin →Use the calculator that matches your marketplace
The Amazon FBA profit calculator estimates referral and fulfillment fees, detects standard size tiers, and calculates break-even ACoS. The Etsy fee calculator separates listing, transaction, payment-processing, and Offsite Ads fees. The eBay fee calculator models final value fees, Promoted Listings, and a minimum offer price.
Use actual packaged dimensions and seller costs whenever possible. Marketplace headline rates rarely include the product, postage, packaging, advertising, returns, or labor costs that decide whether a sale is worthwhile.
How to use these guides
- Choose the marketplace and enter a realistic selling price.
- Add every cost paid per order, not only the marketplace fee.
- Check the dated assumptions against the linked official policy.
- Stress-test advertising, returns, and a lower accepted price.
- Confirm an important decision with a current seller statement or the marketplace’s official tool.
FreeFindy is independent and focuses on US seller scenarios. Results are planning estimates, not tax, accounting, legal, or payout advice.