Go buy a rubbermaid tub from Wal-mart for 10-20 bucks(Even though it's the cheapest cage to get, it's probably the best thing to use for environment controll) Then get 1 digital thermometre with probe to place inside the hot side hot box, then get a 2nd Digital Therm/Hydro combo to read ambient and humidity. If your not into wires then buy an UTH=Under The Tank Heat Pad and all you have to do is plug it into the wall.

Tub - $20 Max
Digi Therm - $10
Digi Combo - $20-$25
UTH - $15-$30 (depends on size you get)

I'd say if you wanted a cheap and easy set up then $60-$75 is what you are looking at.