<prompt> Human: Hello everyone. Im trying to educate myself on the topic of credit cards I never had nor considered having one before but theres something I just dont get.When I open a checking account and deposit money in it, the bank will have to spend some money to keep my account open - IT stuff, call centers, etc. etc. However, the bank will investlend the money I deposited and earn some money out of it, and that gain is greater than the costs they run into. Therefore they make a profit.When I use a credit card and always pay back my debt in full at the end of the month, however, I dont understand how things work. Say I buy something for 100 using my credit card. The credit card issuer will spend 100 out of their pocket, and a few weeks later Ill give 100 back to them, not a penny more. So they dont earn anything, however they obviously have costs to keep my card working. How can they do that? Do they just live off people that fail to pay back their debts? But then those people have a hard time getting accepted for a credit card in the first place. I dont get it. Are there any added fees you have to pay that Im missing?Also, another big question. It seems that a lot of people would much rather use their credit card than their debit card when making purchases. Why is that? So far it seems to me that credit cards usually give some nice rewards such as cash back. How is this even possible?! How can the credit card issuer afford to give me money? Other benefits apparently include stronger fraud protection and reduced interests on future bigger loans such as a mortgage. Are those the reasons people prefer to use credit over debit?Thanks to anyone that will take a minute to answer me. I know Im missing something when everyone owns or would like to own a credit card.EDIT: thanks to everyone, youve all been quick, kind and helpful : What I learned today: merchants pay quite a high fee when I pay by credit card, however they allow me to do that in order not to lose potential customers customers like using credit cards over debit cards in case anything goes wrong card gets stolen etc.. Also, rewards benefits! credit card issuers make a profit off the merchant fees and the high interests that a lot of undisciplined people pay.Thanks again. Im not in a good financial situation, however Ive made giant improvements over the last year thanks mainly to this sub Im a pro lurker and Im basically a new person. Ill try and apply for a very basic credit card soon to start build a little credit history and protect my bank account from fraud. Have a good day everyone!  <response>: Stores pay a percentage, usually 3, to accept credit cards. 