Back when I was hour building in FL many moons ago the following website was invaluable:-
AirNav: Aviation Fuel
Trips usually involved a stop at Okeechobee to fill her up with fuel as it was much cheaper than anywhere else at the time. On a subsequent hour building trip through California, Nevada and Arizona I basically used the above website as a road map. Had a list of places all in the back of beyond where I knew I could get cheap juice. The cheap ones are generally all self service so you taxi up and swipe your credit card just as if you were in your car.
This is the sort of thing you would pull up beside and swipe your card.
Self Serve