Your Nomad story took me back. I worked at a full service station in the early 80s, barely old enough. We had to ask everyone to pop their hood so we could check their oil and fill the windshield washer fluid. Oil top-off was free if it didn't need a whole quart, but that top-off came from a jug of the run-offs from various prior "emptied" quarts. Windshield washer free fill-ups were only a small portion actual washer fluid, mostly water. We were supposed to check air in the tires, but we would skip asking if the owner wasn't watching. We had a deal if we couldn't find something immediately (gas cap, oil or whatever), we would grab a rag to act like we were doing something important and walk back into the shop and ask the old guy. This way we didn't look stupid. Of course the old guy made more fun of us than the car owner would I'm sure, but it made everyone feel good.
Half the folks that bought gas were on store credit. We would take their names and just put their total on a slip that the owner would add to their paper credit sheet. At the end of the month he would mail their bills. Each month we would have a list of no-pays, so if they came in for gas we would have to haggle with them to see if they would pay. One fill after a no-pay month was allowed, but after that we had to tell them no more gas. That created alot of drama.
Thanks for memory lane, wow.