Mercari fees explained
Mercari US charges a 10% selling fee on the item price and a payment processing fee of 2.9% + $0.50 on the total the buyer pays. Mercari has changed its fee model several times, so check the current rate in the app and edit it here if it differs.
Offering free shipping means the shipping label comes out of your side, so enter it as your shipping cost.
FAQ
How much does Mercari take from a $40 sale?
About $5.66: $4.00 selling fee plus $1.66 payment processing, with no shipping charged.
Can I change the Mercari rates?
Yes. Open Edit fee rates and type the rates you see in the Mercari app. They are saved in your browser.