Which they don't and also it's illegal. You can charge less for cash, but no one does that. (Except your one or two examples out of the thousands of stores)
>Which they don't and also it's illegal
source? because there are tons of gas stations that offer a "cash price" and a "debit/credit card" price.
It's not illegal, but it is against Visa and Mastercard's rules, to levy a fee or surcharge to use a credit card. What IS illegal is to prohibit merchants from offering a discount to induce customers to pay by cash or check, which is why merchants that do so don't end up having their Visa and Mastercard contracts cancelled.