Other than routine maintenance, not much.
I put in a new clutch at 98k (cheap part, expensive labor), new tires when I purchased it, and new brake pads.
Steering was a little hard to keep aligned, needed to redo the rack and pinion bushings shortly after purchase as well. At 103,000 miles the alternator went, but at about 80 dollars (an easy self install) that wasn't a big deal. The air conditioner needed some recharging with refrigerant, ran for a year with the recharge until I sold it. A mechanic couldn't find a leak.
I bought the car from a reapo agency after another driver's insurance (from an accident where they were at fault) paid top dollar for my totaled 1983 Toyota Tercel Wagon. A short time later, the shifter bushings wore out, causing the gearshift to have a loose feel, but that wouldn't have cost too much to fix had I cared. I guess I bought the car at a point where it needed some consumable parts replaced: clutch, tires, brakes, etc. so that's to be expected. The car also came with some electrical quirks; the previous owner had screwed with the wiring, messed up the engine kill switch and rigged the engine fan to run full time. Also, by the time I sold it the motor and/or transmission mounts felt like they could do with a check up; a quick start into first gear caused the engine to jump up, literally, maybe a cm or two. but careful clutchwork made that easily avoidable.
All put together, I'd still have the car except I'm starting college and figured I could do without the hassle and expense of insurance and inevitable repairs. My only real complaint- the car could've used more power. Above 70 mph, fourth gear revved the engine too high and acceleration in 5th felt dangerously slow. Not a car to pass trucks on rainy interstates with. But that's the trade-off for 33+ mpg on the highway. An overall good experience, but I wouldn't trust it to last 20 years and 250,000 miles like my tercel!