The best tip is to put your gas card away for awhile. Find out where the cheapest gas is in your area and shop at that station, even if it means paying cash. Even if it means driving a few extra miles. We are creatures of habit, and tend to stop at the same station or two regardless of what happens to the price. We gripe because our station just went up to 3.57 - but yet ignore the station 3 blocks away at 3.32.
Case in point - the stations below are within a 2 mile area. If the price of gas is so bad why are the highest priced station not seeing a major drop in business? They should be left scratching their heads wondering where their customers are, and the cheaper stations should be pondering hiring some more help to handle their increased business.
3.57 Shell
3.51 Shell
3.51 Chevron
3.45 76
3.39 Texaco
3.32 Arco (2 blocks away from the 3.51 Chevron)
I don't necessarily agree there. My car runs at about $0.13/mile for gas. If I go 3 miles each way out of my way that's the equivalent of $0.08/gallon extra for a 10 gallon fill-up. Maybe its worth it, maybe its not. It is rare for there to be more than a couple hour lag between when the first station raises its prices and the last does around here. I used to have an independent station near me that was about a day late, but they went out of business (probably because everyone dashed there and sat in line when the gas price went up).
As for the fuel temperature, it always seems about the same in the tank. I have to be careful in the summer when I fill gas cans because the gas expands about 0.1%/°C, or about a pint on a six gallon can for a 36°F rise (55 to 91). If I fill the can to the top with cold gas, it will overflow once it warms.
The cheapest gas in town just happens to be the station that uses my gas card. And I get a rebate from the card.