If you're not in a fuel rewards program, then you need to be. Sometimes stores will reward you just for doing the things you'd normally do.
For example, one store with a great rewards program is Lowes Foods. The grocery store will give you 5-cents off each gallon of gas once you spend $100. You get another 5-cents once you spend another $100.
Maybe you're thinking you don't need that many groceries. Well, that's the best thing. You can double dip with this program. Most gift cards will also count as a qualifying purchase towards the rewards program. You can even purchase gas cards towards your gas discount.
The discount at Lowes Foods is time sensitive and resets once you buy a tank of gas at Wilco Hess gas stations.