Prurealtyaz -
For that amount of money you will be very hard pressed to get a camera, light kit, green screen background, tripod (don't forget that), microphone, non-linear editor, etc...
You could look on eBay but you could get ripped off very easily at the price points you're looking for.
I would suggest putting the $900 into a decent consumer grade camcorder (there are lots of threads on this forum - do a search), cheap WalMart variety tripod, some cheap Home Depot shop lights and a decent non-linear editor of the entry level type (Sony has Vegas Movie Studio for less than $100 and I know others also have entry level offerings). You can download and try all of Sony's products here: http://www.sonycreativesoftware.com/download/trials (30 day fully functional free trial). I'd also forget the green screen for the moment and just find a nice setting to use as a background (like your front reception area if in an office space, or even your living room at home).
Also, don't forget you will need to learn to use all of the above.
Another option for you (assuming video is not your business) is to look around (Craig's List is a good place to start) and see if you can find a local serious amateur trying to go pro who will give you a decent video for inexpensive rates (I started this way - I used to charge anywhere from $200-$500 per video, depending on length, complexity and time involved - like videotaping).
Good luck.
