Can Merchants Charge a Fee to Use Debit or Credit as a Form of Payment?

These answers differ from what I've read. Here is the link:

I have seen this question a lot lately. And, it seems the question always comes from someone on CA. Whether it is legal or not, I have no idea. You can probably contact your states Attorney Generals office and they might be able to steer you in the right direction, but, it seems more small businesses are passing these debit or merchant fees onto customers. Times are tough!

Of course it is legal. The bank charges small establishments for the card processing service. How would you feel if some idiot came in and insisted on making a $1.50 purchase with a card but the bank charged $1.50 for the transaction? You've made nothing on the sale

The merchants get charged a fee for each debit / credit transaction they process, they are just passing this fee along to the customer. There would be no state statute making this illegal. There may be a clause in their merchant account agreement. But since there are hundreds of difference merchant processing companies and each has their own contracts, there would be no way to know if the merchant you are going to is breaking their contract. There is no way for you to even know who their merchant processor is.