The American automakers have made too many cars they can't sell. So the rental companies are getting great deals on their inventory. And they are passing those savings on to you. If you use a very simple trick, you can get an even better deal whether you rent a car regularly or just every now and then.

For car rentals, priceline.com is a great tool to use. At Priceline.com, you can enter prices you're willing to pay and see if any of the rental companies bite on your offer. If one of the companies agrees to your price, you're obligated to rent that company's car. So make sure your plans are firm before you put in an offer.

The best way to use priceline.com is to visit the other travel sites, such as Expedia, Orbitz, Breezenet, or Hotwire. Then call the companies individually and see if they're offering any unpublished deals. (Make sure you call the specific rental office you'll be picking the car up from, as individual locations will often have special deals.) Once you've done all your legwork and figured out the very best price you can find, then it's time to hit Priceline.

Since you already know the cheapest price you can get through other means, you have a top dollar figure to work with. Where most people go wrong on Priceline is they keep bidding the price up until someone accepts it. But that price may be higher than what you can find elsewhere.

If you do your homework first, you'll know where to stop, and you can start low (say $10/day) on Priceline and work your way up. As you work your way up, also see what you can get on upgrades. Some rental companies might have an overstock of upgrades and will give you a deal on those, but not on some of their cheaper cars. It really just depends on the situation of each company.

So once you're ready to go on vacation, don't hesitate to rent that car. You can get a great deal and really relax and enjoy your trip. Follow a few simple steps online and you'll beat the price you would get from any travel agent or website. It really is that simple.