If I was really pushed for the cash, which mostly I am, I'd go with a USED compressor from my local junk yard. I would NOT change the receiver/drier. If I didn't have a vacuum pump I'd "purge" the system by blowing freon in one pipe and out the other end. Then while there is still a bit of pressure in the system (can of gas slightly open feeding the inlet side) I'd tighten/connect all required fittings to seal it all up.
Then I'd start dumping the gas in on the low side. I would probably turn the can upside down initially and introduce liquid freon at first. But thats somewhat risky and depends on what type or kind of gauges (if any) and additional devices you have to keep the liquid from becoming a problem and damaging the compressor. Plus, you gotta have kind of clue about what your doing. Oh, I think I'd add some compressor
oil to the compressor or introduce it to the system as well in some way. Hard to tell how much, if any,
oil the system has lost or the junkyard compressor had in it in the first place. You could try draining the compressor and then measuring the correct amount of
oil back into the compressor, then add a little more for the system (just to be sure).
Now the BIG problem with the Cherokee is the evaporator drain. If that get's plugged up the water spills out of the evap and onto the passenger side floor, soaking the rug. Punch a couple of holes in the floor for the water to run out of the passenger foot wheel area,,,, just sayin'...
Normally you would blow out with air or run a wire up through the drain to clear the blockage, that aint gonna happen on the Jeep. Your pretty much screwed. Technically you have to remove the evap to clear the drain (remove the dash, etc. a monster nasty PITA project). Here's my thinking on that, there HAS to be a way to drill a hole in the dang frame to access the stupid drain pipe and blow it out and ream it out with a wire. Problem is, WHERE do you drill said hole? Would said hole even work? I sold the Cherokee before I could find out but AFTER I removed the dash and the evap, cleared the drain and then it plugged up again a month later.
I have nothing good to say about the Cherokee from that experience, all though, I thought the V8 was pretty cool, loved the power and the 4 wheel was dam good in the woods. The AC sucked really really bad...