Is it legal in New York State to add a fee for use on credit card purchase?

No, it is not legal in New York State to add a fee for use on credit card purchases.

According to the New York State Department of Financial Services, "A merchant may not impose a surcharge on a consumer for using a credit card." This means that merchants are not allowed to charge extra for customers who use credit cards to pay for their purchases.

There are some exceptions to this rule, however. For example, merchants may be able to charge a surcharge if they are required to do so by law or if they are able to show that the surcharge is necessary to cover the costs of processing credit card payments.

If you believe that you have been charged a surcharge for using a credit card, you can file a complaint with the New York State Department of Financial Services.