All interest rates are not created equal. Some people get charged more interest, and some get charged less. Obviously, you want to get charged less. The interest rate lenders charge is based largely on your credit score -- a number that's assigned to you based on how much other debt you have and how good you've been about paying bills on time. Lenders use the score to assess how likely you are to pay them back. If your score is low, they'll think you're not likely to repay the auto loan and charge you more money to cover that risk. 

Young people often have lower credit scores than older people, even if they've been good about staying out of debt and paying their bills. That's because young people don't have long credit histories, which makes it difficult for lenders to tell how much of a risk they are. As a result, people without long credit histories can be charged higher interest rates too.

You wouldn't just apply to one job or one college, so you shouldn't apply to just one lender for a car loan. Contact your bank, local credit unions and other lenders to find out what they're offering. You'll have to fill out loan applications, which will ask for your employment history, income, expenses and debts. Do not be tempted to exaggerate your income or misstate your expenses. Everything you fill out on a loan application will be verified and lying will get you into serious trouble. The lender will pull your credit history and credit score and make you a loan offer based on that information. 

Take some time to go over all the offers. Don't just look at the interest rates -- avoid offers that charge you a lot of fees. Also, watch out for loans that have a prepayment penalty; that's a charge that you'll owe if you pay the loan off early. Paying the loan off early may not be something you'll be able to do, but if your long-lost Aunt Maybel dies and leaves you a fortune, paying it off could save you a lot of money -- and you don't want to pay extra to do it.