If you live in a small town it is not unusual to pump first and then pay. If the owners know you it is a normal thing.

Even as big as my small town is there are at least two stations I know of that will do this if the owner knows you.

I also know of some larger stations in Dallas that will let you do this. But God help you if you try to move your car before paying. I was filling up when it looked like the SWAT team pulled in and surrounded some guy who was moving his car from the pump to a parking space in front of the building.

He didn't pay before moving his car.