If you’re like most Americans, offers for credit cards arrive in your mail on a daily basis. Why are credit card companies so eager for your business? There are many reasons. Credit cards, for one thing, are not free cash. Funny enough, many customers think of them this way, and that—aha!—is how credit card companies make their money. You’ll notice when you read through the fine print about credit cards that there are varying APRs, or annual percentage rates. This refers to the amount of interest you’ll pay on credit card charges if you don’t pay your monthly balance in full. Think about the last time you went shopping. Did you look at the tags and make sure everything you bought could be paid with your monthly paycheck? If not, you are a credit card company’s dream come true. You see, these companies bank on the chance that consumers will use their credit cards to buy more than they can actually afford at the time of purchase. When the bill comes and it can’t be paid in full, the customer pays interest on this borrowed amount, and that interest accrues daily. This money goes right into the credit card company’s bank account. With thousands of customers falling into this predicament on a monthly basis, you can see where the companies get rich quick. But how can you avoid falling into the credit card trap? A little forethought and budget planning can help you prevent paying interest and still allow you to benefit from credit card perks. Take mileage credit cards, for example. Most airlines offer credit cards that earn you frequent flier miles based on the number of dollars you spend. Enticing, right? Sure. Just be careful to know how much you are able to spend in a month, and don’t let yourself go over the top. It’s easy to check your credit card balance online or by telephone. Know when the closing date is for your monthly statement, and make sure you stay below your limit. That way you can take advantage of the bonus without digging yourself into a rut. Speaking of the credit card rut, let’s go back to that interest thing. Did you know that interest, if left unpaid, also accrues interest? Take a look at this example. You have racked up $10 in interest on your credit cards in one month, based on a balance of $100. (This assumes a 10% monthly interest rate.) Because you leave that unpaid, the next month’s interest accrues on the new balance of $110. That means the next month you owe an additional $11! That’s a $21 total fee for your $100 in purchases. Did you really find a bargain when you bought that jacket at 20% off? Probably not. If you buy responsibly and keep track of your purchases, you can avoid credit card traps. Be a smart consumer, and credit cards can work in your favor. Jeff Lakie is publisher of a website providing information on Credit Cards online. We provide information on Creditors and other online financial information.