1. My local area Speedway is selling $25 gift cards for $23 thru Jun 30 - they call it a "Graduation Special" - these cards work in the gas pumps. I don't know for sure but I assume there's a good chance that this promotion is available at most or perhaps all of their approx 1700 Midwest stores, see http://www.speedway.com/AboutUs/AboutUs.asp

2. Assuming that gas is $2/gal then getting $25 worth of gas for only $23 would save about 16 cents per gallon

3. An added bonus is that Speedway DOES accept Diners Club, I'm buying enough gift cards to last me the next year