Buy gas when the temperature is cooler, such as early in the morning. No, the price isn’t cheaper, but you get more of the product for your money.
How, you ask? Gasoline “contracts” (for lack of a better, more scientific, word) in cooler weather and expands in warmer weather. That’s why, if you leave a gas can out on a hot day and don’t vent it, it will expand and, eventually, explode! (Remember that part of the make-up of gasoline is gaseous.)
What does all this matter? Remember that a gallon is unit of volume, not weight. When you get more of the product (in this case, gasoline) in less space, you are getting more for your money.
This tip won’t save you much each time you fill-er-up, but, over time, it will save you a lot. If you are going on a long trip, this could save you several dollars off your budget (can you say, Olive Garden instead of Hardee’s?)!--Adam