150K on the odometer is used but not worn out, assuming a decent level of maintenance.

Stuff that I would look for includes RUST at the top of the list. Rocker panels, front footwells, rear wheel wells, and under the back bumper are prime locations to look. Don't panic if you see rust; just be prepared to deal with it.

The engine and trans are pretty close to bulletproof at 150K. If the engine is awash in external oil leaks, then flame trap service has been missed. Smell the tranny oil - a burnt smell is bad news, but if the oil is just dirty a DIY flush will take care of that. Worst case, you can usually find an AW70 in the boneyard for $350 or so. Try to find a Neon tranny for that price!

Cooling system - look for water pump leaks. The rad will have to be replaced, probably before 200K. If cooling system service isn't kept up, a head gasket leak isn't uncommon, but it's usually not fatal, either.

1990 still had the older design AC, but your profile suggest you're in the Pac NW, so robust AC performance might not be a strong need for you. Retrofitting for R-134a isn't all that expensive if you need to upgrade.



Biggest deterioration area (IMHO) is suspension bushings. Nearly all can be replaced by the shade tree mechanic with a bit of guidance, and without major expense.

1990 is past the mid-80's "biodgradable" front wiring harness. You may need to replace the odd wire here or there, but nothing systemic.

Trim parts are maybe the biggest void in the aftermarket, but the actual stuff to make the car go and stop are in good supply.

Overall, if the car is reasonably clean, free of serious collision damage, and appears to have been maintained, $1250 sounds like a very fair price. I would expect to throw a grand into the car over the next year (re-do brakes, suspension bushings, struts + shocks, maybe cooling system) as forward-looking preventive maintenance.
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In God We Trust. Everyone else, keep your hands where I can see them.