In my view - cars from the late 80s-early 90s from the premium brands (BMW, Audi, Merc, VW, Volvo, Saab) are the ones worth buying to run on the cheap. Mechanically they are simple and well engineered, and they aren't filled with expensive to fit electronics. Manual windows, radio and sunroof. That's your lot.

What you do is narrow down your potential problem areas to:
Chassis - rust
Body - rust
Clutch - slip
Brakes - do they work, or need replacing soon
Engine - blue smoke/white smoke - idle problems - clean reving

Mind you, I wouldn't go into "bangernomics" if you don't know how to do some basic work yourself.