I agree with Westtown Willy, buy one local so you can check it out in person.
Go during daylight hours, make sure it is not raining, take a small hammer and a flashlight and do not be in a hurry. Wear old clothes and be prepared to lay on your back and tap away with the hammer. A small magnet will also help you find any body filler used to repair sheet metal damage.
I really am quite shocked at the prices for TJ's down south. Here in Nova Scotia (east coast of Canada) the prices seem way cheaper. While these vehicles do live in a rust zone most owners around these parts take precautions with undercoating and if done right the frames will last for a long time.
I paid 6 grand for my 2004 and the frame is excellent and minimal body rust. The thing is black underneath so its been well undercoated and oiled. One small hole in the drivers side floor but I can get a stamped floor pan for 145 bucks which is the plan. Whoever fixed the floor pans in the jeep you sent back should never be allowed around a welder again, truly a horrible job. Had it been done correctly it would have at least given you the confidence that the rest of the repairs were done correctly, but I am doubtful of that.