Some parts are a little expensive. Renix Jeeps can be a little different. If I were looking for another XJ, I'd be looking for one newer than 1991. That's the first year of the HO motor.
Rust will be a problem in areas with snow. Heck, even down here in Florida, rusted floor boards are still expected. The passenger side floor board has 2 things attacking it, one from the top and one from the bottom. From the top, you get runoff from the AC, from the bottom, you get heat from the exhaust.
Stay away from the pressurized coolant tank models. Again, that's also the Renix Jeep. They have a massive rats nest of coolant hoses that often fail.
I bought my Jeep for $600. It needed a rear block freeze plug. It still has to be finished up, but overall, it won't cost a heck of a lot more to get it running again. It needs floor boards. They're like $150 a side for molded ones.
My Jeep wasn't an atypical purchase in these parts. They're very easy to find running under $1000, and ready to daily drive for under $1500.