"Rosspilot" wrote in message
...
I take credit card payments all the time and can say with certainty that
both
Mastercard and Visa prohibit their participating merchants from charging
more
for using the credit card. It may not be illegal, but it violates the
merchant's contractual obligation to MC and Visa.

Unfortunately, either not all merchants are bound by that requirement, or
not all merchants abide by that requirement. There is no shortage of
retailers who DO charge more for credit card purchases.