system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it that, at some gas stations, it’s cheaper to pay with cash instead a credit card?

Have noticed this recently at a few gas stations in my area - it will be several cents per gallon cheaper to pay for gas with cash rather than a credit card. Why is that?
gpt
Credit cards have fees.  If you pay cash, the merchant avoids these fees.   A cash discount also requires you to enter the store (where they sell things like soda and candy, that have a much higher margin than gas)