But, to some people that still does not make it right.
"I don't like it, but sometimes I am in a hurry," says. "I go ahead and pay it, but it doesn't make any sense to me. It's not right."
Merchants prefer not to take credit cards because they have to pay a fee for the privilege, sometimes as much as 3 percent for smaller businesses. So, if the retailer can charge more for a credit card purchase or convince the consumer to pay with cash, they are ahead of the game.
But, is it legal? The answer is yes, but it takes some pretzel logic to get to it.
"In California, a merchant can give you a gas discount in order to encourage cash spending. But, it is actually illegal in California to surcharge a credit card," explains.
So, if it is a discount it is totally legal, but if it is a surcharge it is not. Joe Ridout with Consumer calls this a "fine line." He says the law was written in large part to keep additional fees from being snuck on to credit card bills.
"Many merchants actually do this. They will tack on a dollar or 50 cents if you use a credit card to pay for something and don't spend enough money," he says.
The law addresses this so now consumers can too. Discounts are fine. Add-on fees are not.