Rule for me was rather simple.
I’d use my mother’s car when she needed me to run errands, and she was responsible for its maintenance and gas and all what-have-you. Except on special occasions, for personal use I had to take care of my own vehicle, the purchase of which, along with insurance, gas, and all the other expenses that go along with a car were entirely my responsibility.
She got really pissed when she found that she’d have to pay out the ass for a driving school that wouldn’t teach me anything I didn’t know after four cross-country moves and driving experience without a license before I could be licensed.
As far as the priviledge of driving went, unless I really pissed her off (i. e., something along the lines of porno or drugs, not little things) if I managed to get my own car (which, through my friend’s dad, I acquired an olds in wonderful condition for $950. Not the nicest thing to look at, but there was no rust and it ran perfectly fine) driving may as well have been a right.