May I suggest, along the same lines, for fue savings is GasBuddy The App. You can set it to find only Diesel or to find Gasohol which they are still calling gasoline. They also have a "pay with Gasbuddy" that I have not tried. You have to allow them access to your bank account. Similar to some of the other pay by phone apps. This gives you additional savings. Like you , I have traveled side roads to get to cheaper fuel, but I use Gasbuddy to direct me, and to give me choices. While you are waiting for the pump to finish emptying your wallet, you can add your own price update or verification to Gasbudy. The more we all use it, the better it becomes.