Utilize your financial knowledge, give your answer or opinion to the input question or subject . Answer format is not limited.

Which credit card is friendliest to merchants?
From experience, Mastercard and Visa charge vendors about the same (around 2%-5%) while American Express and Diners Club are astonishingly expensive (6%-10%) and you'll find that few small retailers are very comfortable accepting these. The variation comes from the volume of trade that vendors provide.  A big retailer will negotiate a very low rate while smaller businesses will be hit with higher charges.