Credit cards are a convenient way to pay for items. They enable us to buy big ticket items like furniture and appliances and pay for them at a later date. Banks (and other financial institutions) issue credit cards and are the ones who are actually buying the merchandise we charge. The banks buy the merchandise, then we have to return the money "borrowed" back to the bank. For the privilege of using the bank's money to make a purchase, credit card holders pay interest on the amount they owe. This  interest rate can be pretty high. The average interest rate is around 18%, but a lot of popular cards (department stores and clothing stores) have rates above 21%. 

If you're just starting out and haven't got into credit cards yet, don't get carried away. Get one card and see to it that the credit limit does not exceed one month's salary. You'll have to keep an eye on this, because some companies will increase your limit on a regular basis to encourage you to spend more.

Is your credit card debt more than you can pay off in three months? Destroy all but one or two of the cards (the ones with the lowest interest rate). There is no need to keep a department store card.

Don't use credit cards to pay for recurring expenses like groceries, gas, or utilities. Not only will you have the same expense next month, but you'll have to pay off the credit card, too.