As a Realtor I can spend a lot of time in my car. I now drive a hybrid but used to drive a 8 cylinder car that only took premium, so gas prices were very important to me. I, of course, learned all the tricks to stretch my gas mileage: fuel up early in the morning (gas is cooler earlier in the day and more dense, so you get a little more of it then), keep the engine tuned and the tires at the proper pressure, etc.

The biggest savings have come to me through the GasBuddy iPhone app however. GasBuddy is a free app that shows all the gas prices at all the gas stations around me. Whenever I need gas, I simply open the app and see who has the best price in the area. By doing this I normally save .10 per gallon and sometimes even more. 

I realize that .10 does not sound like a lot, but it definitely does add up. I also like that the GasBuddy app will tell me the trend in gas prices, along with having drawings for free gas. And don't forget to charge your gas purchases with a card that gives you cash back. Make every penny count!