[timdorr]

I haven't ever been subject to differing costs between credit/debit card and cash prices, with the sole exception of the liquor store. Are there specific stores in the US that do this?

[etfb]

Credit cards have fees -- interest, account-keeping fees, and so on. It's why banks like them.

[pfisch]

Only if you don't pay them off immediately, or you agree to an annual fee for specific benefits.

[lmm]

Depends on the card. I've got one that charges interest on purchases even if they were made in that same month. (In general you're right though)

[alimoeeny]

have you ever used your credit card at gas station?

[timdorr]

I own a Model S :P

But yes, and most gas stations I've ever used don't have a cash and credit price.