I forgot to mention:

If you can, make arrangements get the car up on a hoist with the seller there so you can look at the rust situation and the stuff VS Tech mentioned. Depending on what you find you might negotiate a cheaper price or maybe decide to take a pass. If the seller is there you can show him/her your concerns.

If you can't make arrangements to get it up in the air at least take a floor jack and a pair of jack stands so you can safely crawl under there and take a look (NO RAMPS - they kill people). You need as good a look as you can possibly get.

Remember, this is NOT a ton of money as far as car sales go but you need to have a realistic idea of how big a bite you're about to take.

I disagree with the poster who made a big deal out of the paint. IF it's really awful and the price is right you can get an OK paint job at MAACO for $1500 w/clear coat if you do the prep yourself. It won't be factory perfect but it's NOT a new car! However, if there's structural (or significant surface) rust it probably won't be worth the effort.

Dan