Soda Vending Machine Smoker - Help, please.

[Gitanorey]

I am currently just starting the process of building a smoker out of an old junk vending machine. I've stripped the inside out of it and need a little help on what to possibly line the inside with (if anything is necissary). I plan on building a fire brick lined firebox at the bottom but that would be costly to do to the entire thing. Any pointers would be greatly apprieciated!