Well... that used to be the case, by law, in California. However, a court case several years ago overturned that law.AmriloJim wrote:BTW, the upcharge for credit card use on fuel sales is actually a discount for paying with cash.
The court found that requiring a seller to describe a difference between the cash price and the credit price as a "discount for cash payment" rather than a "surcharge for use of a credit card" was an impermissible restriction on the seller's freedom of speech. Since stations here almost always post both prices, and since the price difference is obvious and wouldn't change regardless of whether you can it a "discount" or "surcharge", the court ruled that there was no public benefit strong enough to justify giving the government the right to dictate how the merchants must describe the difference.
I've seen a few stores (not just gas stations) change their policies since that court decision... their posted or advertised prices are "cash" prices and they explicitly say that credit card prices are 2-3% higher. This is still fairly uncommon but it does happen.
ARCO made an interesting decision along these lines. They simply don't take credit cards in California... just cash, or ATM debit (with a debit free that's per-transaction, not per-gallon). Only one price to post, per grade of gasoline.