I use truck stops wherever possible because I hate having to wait while a small hose fills my tank. Just remember that if you use truck stops, observe protocol and as soon as you finish pumping, pull up like the trucks do so the next guy can start fueling. There isn't a $ limit in truck lanes. I use Pilot/Flying J because I have a frequent fuel card allowing me to start the pump without having to go inside. After fueling, I pull up and then go inside to pay. Occasionally, I get behind RVers who don't respect that protocol and it is irritating. I understand how the professional drivers feel when RVers do that. Please pull forward as soon as you are finished fueling.
As for Sam's. When I leave home, I top off at a Sam's club in Vacaville, and when returning, I always fill up there. Yes, they have a max of $100, but I restart the the pump again. I don't like it only because it is an auto pump, and it is slow fueling. It is the closest to home, so I use it.