You get what you pay for with a lift. If you go with a cheap lift on Ebay like a Tuff Country, Rough Country, etc. you WILL bend brackets, punch holes in the diff, etc if you wheel the truck hard.
Expect to pay at least $1000 for a good RBV lift...one that extends the radius arms. That does not include shocks, pitman arm, or brake lines.
Duff, Skyjacker, and Superlift are all excellent quality kits. The Superlifts need some mild strengthening of the radius arm tabs, and driver's side drop bracket tabs.
Look for used lifts. I picked up a Superlift 5.5" kit with extended arms for $400. It was in new condition. If installed correctly and the lift is a good quality one, a 20 year old lift is just as good as a new one. People frequently SAS their already lifted RBVs, and this leaves a surplus of reasonably-priced, lightly used kits that are frequently offered here on TRS.
My thoughts on body lifts:
Body lifts are great and should be used in combination with a suspension lift. Body lifts have the following advantages over suspension lifts: You don't need to mess with steering, they are cheap, they give the clearance needed to run a transfer-case doubler, they make it easier to work on the truck, as far as getting to things like bellhousing bolts, they increase your CG less, they result in more low-CG frame and axle clearance because you can run larger tires.