[kileywm]

Legality aside, which other posters have covered:

I dealt with a local mechanic (small shop) earlier this year who, when it came time to settle the bill, said he will do debit/check for no fee, or a 2% fee for a credit card. In addition, some local gas stations advertise cash rates for fuel, which are slightly discounted vs credit cards.

It's an interesting practice that I don't mind. Ultimately it provides transparency and options to consumers who may be unaware of interchange rates and such that factor into day-to-day transactions.