I do know the "true bottom", but it is 200 pages of documents, and will depend on the mix of debit cards, Amex, and card levels such as Business/Signature/etc,

I do know the "true bottom", but it is 200 pages of documents, and will depend on the mix of debit cards, Amex, and card levels such as Business/Signature/etc, and international, and average transaction amount. If you are interested Visa alone, then the latest fee schedule is here: http://usa.visa.com/download/merchants/Visa-Interchange-Reimbursement-Fees-April-2014.pdf http://usa.visa.com/download/merchants/Visa-Interchange-Reim... 1.45%-1.65% + $0.10 is a very common interchange for retail. The 1.75%+$0.00 pricing is going to be zero margin for them. If some merchant just uses Amazon for Amex, they will lose on that merchant. If the merchant primarily serves debit card customers, Amazon will make a small amount of money.