I have an older Sunline Truck camper (85) that has worked out unbelievably for me, and I tow a H16 behind it. Mine has a shower, toilet, fridge, stove, and sleeps 4. It also is a hardside, so it doesn't pop up. We didn't want to have to deal with drying the canvas when it rained, or possible leaks. It also is a lot warmer in cooler weather.
The big concern is getting one suited to the size of your truck. If you have a half ton truck, then a pop-up is probably what you can handle. You can also check out sunlite (
http://www.sunvalleyinc.com/trucks.htm), or Travel-lite (
http://www.travellitecampers.com/index.html)for other lightweight campers. My camper weighs 2000 lbs, and I have it on a 3/4 ton truck. With a half ton, you are looking at something in the neighborhood of 1400 lbs.
www.rv.net is also a good resource for researching truck campers.
Finally, to know the value of the camper you are looking at, you can check out the NADA guides. (
www.nada.com) In addition, ebay has quite a few posted if you just search for truck campers. Good luck!