If you have a AAA credit card, they give you a 5% savings on gas when you "pay at the pump" with their card. I have one and have been using it for months and they take the 5% off when you get your bill. I only use this card for gas too so I know just what I'm spending every month for the 4 cars in the house.

I have no ties to AAA except that I do insure with them, mostly for the convenience of being able to do DMV things at their window since I have bought and sold a lot of cars over the years and it saves me a lot of hassle.

Just my .02 worth.