OKLAHOMA CITY - We see the commercials all the time from dealerships promising to get you in a car, no matter your financial situation. Before you drive off the lot, here are four things Consumer Affairs says NOT to do before buying a car.

The first one I hear from frantic car buyers all the time.

* Don't drive off the lot until your financing terms are set in stone. Some dealers will let you leave the lot with a contract before it is final. You later get a call saying the low interest financing they originally promised wasn't approved.

* Don't rely on verbal assurances. Make sure you get everything in writing and understand what you're signing.

* Know the market. Don't accept a finance contract without checking to see what the going interest rate is for your credit category. The more desperate you seem, the more likely they'll quote you a high interest rate.

* Carefully consider the extras, like extended warranties, GAP insurance or credit life policies. Consumer Affairs says they generally aren't worth what you paid for them.

* Make sure you know whether your loan interest is pre-calculated. In far too many cases, people with bad credit end up with a loan where the interest is pre-calculated. When loans have pre-calculated interest, your payments may go solely to interest for as much as one-half of the life of the entire loan.

* Watch out for penalties. Know whether there's a prepayment penalty written into your contract. Depending on how bad your credit is, you may want to go ahead and accept a loan that includes prepayment penalties. But be prepared: if you pay the loan off early, you may face an additional charge of $25 to $200.

* To get a real-time snapshot of average car loan interest rates for your FICO score, use this loan calculator: http://www.myfico.com/myfico/CreditCentral/LoanRates.aspx