Gaspricewatch.com offers the following tips on how to buy gasoline:

1. Buy gasoline during coolest time of day, either early morning or late evening. During these times, gasoline is densest. Keep in mind that gas pumps measure volumes of gasoline, not densities of fuel concentration. You are charged according to "volume of measurement."

2. Normally, the best time to buy gasoline from a pricing point is Wednesday morning. The prices are usually moved up for weekend by the oil companies. By Wednesday, you have had three days of competition setting in among the stations to help drive the price down a few cents.

3. Most stations generally raise or lower their prices in the morning, around 10 a.m. Expect a rise to occur on Thursday morning.

4. Some stations are quick to raise prices when they are going up, some are slow to go up. If you find that the price has gone up when you go to lunch, try and find one of those slow movers in your area so you can still purchase the cheaper gasoline.

5. Choose type and brand of gasoline carefully. Certain brands provide you with greater economy because of better quality. Use the brands which "seem" most beneficial.

6. Avoid filling gas tank to top. Overfilling results in sloshing over and out of tank. Don't fill the gas tank past the first "click" of the fuel nozzle, if the nozzle is automatic.

7. Avoid purchasing at exit ramps for highways, especially during holiday travel. These stations may be convenient but they know they have a captive audience. Try to fill up at your local station before you leave town.

8. If you have to buy on the highway, try to buy at the border stations when traveling between states. Many times these stations are very aggressive at trying to gain your business and many can take advantage of differences in state taxes.