Fill you tank in the morning. You get more for your money....

Gasoline is a gas. Duh. It expands when it warms with the heat of the day. Therefore, buy the concentrated morning fuel.

I'm not making this up. I read it somewhere.

which could be the case...but gasoline is a liquid. I'm not sure how much liquids expand with heat, but if anyone knows please share!

Actually, I just googled to double check and several sources agreed that gasoline will expand on a warm day. That's why you should never top off your tank - it could overflow.

I didn't link to this because it came with a bunch of pop ups but here's some money saving tips about driving.

13 Easy Ways To Save Money On Gas

Reduce Your Driving Costs by 25% or More
The cost of commuting, running errands, or vacationing by car has risen sharply with higher gasoline prices, but you can significantly lower your driving costs with these gas-saving tips:

1. Don't drive a gas guzzler. Do you really need that SUV? Six cylinders instead of four? How about that big pickup truck?

2. Keep your car properly maintained and tuned. A poorly tuned car can use more than 25% more gas.

3. Use steel-belted radial tires. They increase gas mileage up to 10%.

4. Don't use high octane gas unless your car is pinging and knocking or you have a high-performance engine and the manufacturer recommends premium gas.

5. Check your tire pressure weekly. For every pound of underinflation, you can lose up to six percent in gas mileage, so if your tires are five pounds underinflated, you'll use up to 30% more gas.

6. Don't top off your tank when pumping gas. On a warm day, gasoline expands and can overflow.

7. Don't warm your car up by letting it idle. The engine warms up faster when driving than it does when idling, and idling wastes about a quart of gas every 15 minutes.

8. Save fuel by combining errands into one trip and avoid backtracking whenever possible.

Wasteful driving habits can double your fuel consumption. Develop gas-saving habits, such as:

9. Always accelerate gently.

10. Watch traffic ahead of you so you can anticipate slow-downs and avoid stops.

11. Coast up to traffic jams by lifting your foot off the gas pedal instead of approaching at full speed and slamming on the brakes. It takes 20% more gas to accelerate to normal speed from a full stop than it does from four or five miles per hour.

12. Don't drive too fast or too slow. It takes 20% to 30% more gas to drive at 70 mph than 50 mph.

13. Maintain a steady speed on the highway. Avoid getting stuck behind slow cars where you have to slow down to their pace and then speed up to pass.

I never fill up just before parking at home or work when it's warm and sunny because the tank will overflow if I haven't driven far enough to burn some up.

However, gas at the station is stored in underground tanks, and I'd bet they don't change temperature much during the day.