Credit cards do not have to end up costing you the earth. So long as you can keep your spending under control, and are able to pay off your monthly bill in full each month, your credit card will probably cost you nothing. Every purchase you make with your credit card is given an interest free period of somewhere between fifty and sixty days. This is the time between when you make the purchase and when the purchases show up on your next monthly bill. So long as you pay for it on the first bill, there will be no interest or financing charge for the purchase.
However, if you do not manage to pay for the purchase on the first bill it shows up on, then you will start to incur interest and financing charges. On credit cards, interest is charged monthly, not annually.
Also, as well as interest and financing charges, credit cards can also end up costing you in other fees. Probably the most common charge people incur with credit cards is interest charges, when they become unable to repay the full balance in full each month and instead, allow the balance to carry over to the next month.
But late payment fees are another way that credit cards ending up costing...