I'm looking at this PA on ebay for $28. But I'm close to clueless as to how this all works. All I know is that I will likely need a CB radio.
http://cgi.ebay.com/CAR-AMPLIFIER-12...d=p3286.c0.m14

So what are all the parts that I need? And where can I get them for the best price while still getting good result?

 

http://cgi.ebay.com/Midland-1001Z-40...=p4295.c0.m299

Would this work? Will I need an antenna too? Will I need more wiring to connect it to the electrical panel under the hood?

 

Splendid idea. That CB should work, but it wouldn't be a bad idea to check with the seller on audio outputs. Some CB's, especially the cheaper ones, only have a small speaker on the front or top. There should be an audio out on the CB, allowing you to run that to your vehicle's stereo inputs, which you'll just run to the PA under your hood. Keep in mind you may want a killswitch because whatever comes out of the CB will be heard outside of your XJ, including incoming transmissions. You can probably run the 12V off of your + batt terminal and to any ground, I wouldn't think it would be a very big draw on the system, but be sure to put a fuse in either way. You'll need an antenna for CB communication, but not the PA. Post a link if you find a good antenna, I'd recommend one that's magnetic so that you can drag it off if you go under trees rather than breaking it. Good luck with the install, let us know how it turns out with some pics.