The mechanic I used to go to had two billing scales, one for cash/check customers and another for people using credit or debit cards. He was a small independent business and the bank ripped him a new one for debit and credit card payments every month so he padded bills to offset bank fees for debit/credit payments to his business. This was back in the 90s and the bank he used for business charged a percentage of the transaction rather than a flat fee per transaction because his business didn't do over a certain number of transactions a month to qualify for a flat fee.