Parts for Z's aren't getting hard to find. There are very good supplies of them, and i have yet to have trouble finding any parts for my 260 and 280zx.. If they break, its because it was rode hard and put away wet ( Thats how a lot of them were treated, and they still live). 500 in maintenance is more than enough... Hell, the cars are cheap enough (You can usually find good ones for 1500) Buy 2 and have one in case that it get broken. Or you could buy a caviler or something that is much more prone to break, and has a lot more expensive parts on it.
Also, he doesn't have new car money. He has 3k, so a new car is out of the question.
This looks like a decent one.. Being an 84, it still has the (Not trying to piss anyone off) ugly dash.
http://dallas.craigslist.org/dal/ctd/3116812034.html