I have concluded that if you have to divert or change route the slightest to use the "discount" card, it simply is not worth the fuel cost to divert and the frequent hassle. I just find the most convenient and accessible station where the advertised price is the same as Flying J or Pilot, and fuel up with a credit card that provides airline miles. Then every now and then, I fly to Europe on the few pennies I may have paid over the GS "discount". My wife and I went to Rome this last Spring for 8 days, and paid airline and hotel costs on the airline mileage earned on a Continental/United Visa which we use for everything and pay off monthly. This system, for us, means less travel hassle in the coach, and a lot of fun using the air miles later. You can also redeem the miles for Apple laptops and many other items, if you don't fly.