You can look at LLLReptile cages or DIYcages, they have some fair priced cages, and from what I've heard they're both pretty good.
As for lighting, and misting system, you can look on Craigslist or eBay and get something used but in good, working condition, or you can just buy it new at your local pet store.
Plants you can get at Home Depot or Lowes or something like that, and the branches you can just get a couple from outside and wash & bake them so all the parasites and whatever can make your chameleon sick dies.
