I am new to the Jeep world and recently bought an XJ to build up as a weekend toy. I had the same idea with mine. We tested several options in my paint shop and found that Dupli-Color's bedliner was the best value/most durable for the money and one of the easiest DIY options. I am including a couple of pictures of my project. This stuff is pretty nasty tho, so if you DIY, have a good setup for it. We put up a portable garage, lined it with painters plastic to seal it up and all had paint respirators on for the project. We scuffed the jeep down and sprayed without primer. This bedliner did not appear to need primers, it had no problems biting into our test materials and has so far held firm to the vehicle. We ended up only needing 15 spray cans of the dupli-color stuff to put 2 heavy coats on the vehicle.
$20 in alcohol/rags/scuff pads/tape (paint prep)
$50 in alcohol for consumption
$135 in paint ($9/can x15 cans used)