I took my carpet out and Herc'ed the inside of the tub. (Herculiner: do it yourself, roll-on bedliner found at Wal-Mart for about $60). You will also need an aditional quart for about $40, botle of acetone...about $10, 80 grit sand paper $5, and masking material. Oh! and a REALLY good set of gloves, my hands were black for a week. So far I really like it. Herculiner has a grit to it, so you don't slip around when it's wet and muddy inside the rig. I can pull my drain plugs and hose my Jeep out. Also, I would swear it has a better sound dampening quality than my worn out, paper thin carpet had. I've even heard of people using rhino, linex, etc. for spraying in their trunks instead of dynamat for those big booming sound systems, so maybe there's something to it. Anyway, if you decide to go through with it, it will cost you less than $150 and an afternoon. My only advice is: Make sure you do the PREP WORK!!!! If you don't sand everything down then wipe it with acetone, the Herc will eventually just flake off. AND, make sure you take your time masking everything off that you don't want Herc'd...This stuff is gnarly and doesn't like to come off seat bealts...i can tell you I learned the hard way.
Anyway, Hope that helps, good luck and have fun.
-Boze