Here's a breakdown of what you'd be looking at spending to set up a chameleon:
http://muchadoaboutchameleons.blogspot.com/2012/03/average-cost-of-owning-chameleon.html
I do think you can set up a chameleon for $200-300, it just depends on what you get, where you get it, and if you know what not to waste your money on. But if you start investing in "upgrades," like an automatic mysting system or the Arcadia bulbs with reflectors, etc., then yes your set-up costs can go way up.
For a new baby in a small baby cage you could get the ReptiSUN 5.0 UVB bulb, and then when you upgrade to a larger cage switch over to the Reptisun 10.0 bulb or look into the Arcadia ones (6%, for example).
The caresheet someone posted in the first reply you got is great, I recommend looking over it because it goes over feeding, supplements, etc.
Make sure to try and get a male chameleon as your first, the added difficulty of egg-laying in females is something we don't like recommending to new keepers unless they feel up to it.
Do not get your first chameleon from a place like Petco, they are usually not in the greatest health. I highly recommend you find a local breeder by asking on the forum or look into what reptile shows may be in your area and hand-pick one in person. Or look into the forum sponsors who offer baby veileds, because they can ship them to your door.
Anything else you need to know just ask!