As well as the $4 fee mentioned, Zip and co also charge the merchant - in my country, 30 cents per transaction and 4-6% commission. Late payment interest is probably just gravy.
With schemes like these, all customers ultimately end up paying for this regardless if you use the service or not as merchants will have to add the costs to their prices.
With schemes like these, all customers ultimately end up paying for this regardless if you use the service or not as merchants will have to add the costs to their prices.