Talk about national sticker shock. A survey shows the average new car price last year was over thirty thousand dollars in the U.S.

Kevork Djansezian, Getty Images

The survey by Interest.com finds many consumers spend too much of their monthly income of a car payment.

"Car expenses, you know, how much you pay for a car or a truck, is usually the second-biggest thing in your budget," says Mike Sante, Managing Editor

He adds that the thirty thousand plus sticker means you'll fork over more than six hundred dollars a month on that loan.

Sante says a car buyer should follow what he calls the 20-4-10 rule. That is, put 20 percent down on the vehicle, never finance for more than four years and make sure total monthly payments, including insurance, do not exceed ten percent of your gross monthly income.