Don't worry. I know exactly how credit works. I didn't say there's anything wrong with it. Just that it's going to cost you more to use credit than for cash. Merchants may want to recoup the loses from paying the fees when the customer pays with credit. Also, merchants pay higher fees when a customer uses a premium credit card as opposed to a regular credit card. But paying by debit card won't have any effect. Using a debit card is the same as using cash. In case you didn't know, from my experience from traveling in the States, all service stations have 2 different prices for gas. One for credit, and one for cash. Which can be a difference of anywhere from 5 to 10 cents per gallon. You'll probably see more of that in Canada soon.