it's all about the loopholes, baby.

You know how sometimes you pay a diff price for gas depending on if you pay in cash or use yo plastic?

So, I just found out that Visa and MasterCard explicitly prohibit merchants from charging consumers extra for paying with a credit card. (American Express & Discover don't.)

But all the cards do allow the station to offer a discount for using cash.

So, all they need to do is increase their regular price & give the discount to the ppl who carry green. Sneaky.