I had a 1958 Plymouth Plaza for a while. There was one guy in town that would work on it. I think his name was Don. There were no signs for his shop. No regular hours. You could call to try and make an appointment, but most of the time the phone just rang and rang. Usually I'd just show up. Sometimes I had to bang on the roll-up metal door and he'd come out.
He would only fix one problem at a time: It didn't matter if I told him 3 things, or 5 things, he would only fix one. I would have to come back another time and tell him about the "new" problem I was having, pretending that I hadn't mentioned it the previous time.
There were no forms, no receipts. When I'd ask him what the bill was, he'd say something like: "Just give me fifty bucks."