You have to ask yourself if you're comfortable with driving a vehicle that's older than you are, which are know to have electrical gremlins (modules that like to malfunction and drain the battery while you're in watching a movie for example), has higher mileage and (given the sale price) is likely going to need some work beyond what is listed in the ad.
As a comparison, I bought a '96 ZJ Limited w/5.2 about 2 years ago from a coworker for $500, it was running but was in need of some TLC. I put about $750 in to the vehicle just to get it in to good reliable, running condition. Remember, this was a vehicle that my coworker was driving to and from work 5 days a week, and was his only form of transportation. That $750 figure is just parts, as I did all the labor and doesn't include the 'value' of the spare set of tires I had installed (take offs from my wife's WJ). There was a couple labor intensive repairs that needed to be done, such as heater core, rear main seal/oil pan gasket, and the ever common 5.2 plenum gasket. Also, I had not even touched the suspension, which was in need of pretty much a complete rebuild. That being said, I drove that ZJ quite often and never had any issues once I got it to that point. I eventually sold it to my brother in law who still drives it to this day, when I sold it to him it had almost 225k miles on it, and is likely closer to 235k now.
My advice, save some money, buy a better maintained/cared for ZJ if that is vehicle you want.
His: '00 WJ 4.7 Limited- stock
Hers: '03 WJ 4.7 V8- IRO 3", 245/75/16 Duratracs