Most of those cards charge a processing fee somewhere between 1.5-3%.
One of amazons 3 main fees is a $0.99 fee per item sold (or a subscription fee).
That alone is 19.8% of a $4.99 small case of water. Which means most sellers probably pay the subscription.
And then theres the referral fee and the variable closing fee.
Think about it, amazon still has to pay those credit card processing fees to charge cards and collect on the items sold. They're going to tack that - plus a premium - onto the seller's bill in exchange for letting the seller take advantage of the marketing empire that Amazon has built.
You could argue that they might get more exposure on Amazon. But judging by the paltry number of reviews, it doesn't seem to be working.
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