Contrary to popular belief, car rental rates are not set in stone. Often, discounts can be found by doing your research, and simply asking for them. Rental companies are eager to rent out cars they are not using. Cars sitting on a lot are not making them any money.

Here are some tips to get best discount car rental rates

1. Do your research. Car-rental research can be done online, on the phone, or by reading newspapers magazines or even your mail. It is important to compare the rates from various car-rental companies. Most car-rental companies web sites, where they will show you rates for various locations. Also check the travel comparison web sites to compare companies against each other.

You can also get on the horn to the car-rental companies, but this takes more time. Check the business and travel sections of your local newspaper and check the inserts in your credit card bills. Often, you will find discount coupons in those places.

2. Book early. If you are planning your trip several months in advance, check car-rental prices available at that time. If you find what you consider fair, go ahead and lock it in. You can change it later, if you find a better rate. Many times, car-rental companies will give deep discounts to early renters.

3. Book late. As the time for your trip approaches, car rental discounts may be found as car-rental companies try to unload their excess inventory. Like I said, cars that are just sitting around aren't doing anyone any good.

4. Pick your car in town. You pay a price for the convenience of picking up your car at the airport. Ask your rental car company, about how much it would cost to pick up your car in town. Normally, free shuttles are provided from the airport to the car-rental location.

5. Get the smallest car available. Determine the number of passengers traveling with you and the amount of their luggage, then get the smallest car that you will all comfortably fit in. Ideally, the car-rental company will be out of this car and will upgrade you for free to the next higher class. You can also ask about complementary upgrades.

6. Ask about discounts. Ask your car-rental company if there are discounts for a weekly versus a daily rental, or if there are discounts for memberships such as AAA, USAA, AARP, or other organizations. If you work for a large company, ask about corporate rental rates.

7. Gas up your car before returning it. I remember when car-rental companies would charge more than three dollars a gallon to gas up your car up on return. These days, that would almost be worth it. However, car-rental companies are charging a whole lot more than that for a gallon of gas. You can save a lot of money by putting the gas in yourself on your way to return the car.

By following these tips, you can get a better rate on car rentals just about anywhere in the world. Have a great trip!