Wow, never heard of such a thing. Did you ask her to show you the policy in writing? Maybe she was just looking to get some $$ for lunch?
"It is a way of saving money ... it helps us keep our costs lower," said AT&T spokesman Mark Siegel. "We want our associates to spend their time helping customers as they are thinking about their wireless plans or looking at phones."
However, this is where things get complicated. Agreements between retailers and credit card processors, such as Visa and MasterCard, prohibit stores from charging more for purchases made with plastic than for those done with cash. However, it's OK under these agreements to offer discounts to customers who pay with cash. Even though they essentially amount to the same thing -- it's cheaper to pay with cash than plastic -- a semantic loophole means one is fair game and the other isn't.
In some states, it's more than just against Visa and MasterCard's rules, it's against the law. New York has a law that prohibits retailers from charging a surcharge for credit cards.