If at all possible take your time & don't rush it. As mentioned, with that budget you're most likely going to be in the YJ market. Most of them for that price are going to have some rust & chances are the rear main seal will be leaking. However, if you can afford to take your time you'll find a clean one. I saw one YJ pass by not too long ago that had a V6 Vortec conversion, no rust, super clean, & sold for only $3500. The guy was in a bind & needed cash. Those don't come up that ofter, but if you can afford to wait they're more that worth it.