I have never come across this. I would call your credit card company and ask. To me, it might make sense for a very small business to do this or if the charge is less than say, $10 or so. It might cost a small business more than it's worth so they pass along that cost to the consumer.

Yes it's legal.

Here is a link that might be useful: Visa explanation of surcharges

We have several gas stations that charge more per gallon if you pay with a credit card rather than cash. Some are independent stations, others are part of national chains.

It is legal. I can pay my NJ taxes with a credit card but they add a% fee. I was able to charge my DD's college tuition to a credit card without any fees, I loved it because I paid the card off each month and I earned a zillion frequent flier miles. After she graduated the school changed policies and they now impose a fee for credit card use.

Yes. It's because firms are charged a % fee on every transaction paid by credit card. They pay it because they get a lot more business if people can pay with a card. However with fees rising and profits getting squeezed, some are passing along the fee to the customer.

Its a customer courtesy to accept credit/debit cards. No merchant is required by law to accept any particular form of payment, but they can charge certain fees. Its common for a merchant to charge a returned check fee as a means of rrecouping their costs of offering that as a method of payment, so adding a ttansaction fee for non-cash payment is just another cost containment for them.

Many small businesses and convenience store/gas stations charge a small fee for plastic. Its all legal.

I have never come across that but I understand that some merchants are charged 2.5% for every transaction. My local family owned butcher shop requests a minimum of $10 to use a credit card. I try to get the cash out before going there because I know it is costing them money for me to use my visa debit card. The money is in my account I just can't be bothered most of the time to go to the bank to get it out.

If businesses were smart, instead of saying they are charging a fee to use a CC, they should offer a discount for paying with cash.

I've seen it more as a discount for not using a credit card vs. an added fee if you do use one.