Another similar notion is with credit card payments for convenience items at bakeries, deli, and pizza restaurants. A company called "4shifts" is notorious for telling owners to place a sign on the register "a convenience charge of 3.5% will be added to the sale if you use a credit card". Add the 3.5% plus sales tax which increases the sale by 8% - 12% depending on the state you live in. 4shifts is also used in major…
That surcharge is also why most credit card terminals default to debit card when presented Visa/MC debit card is used. Debit cards incur a lower fee from the network than the credit card fee. Of course the customer also has less recourse using debit vs credit when it comes to chargebacks, extended warranties, etc.