I used a Canon T2i with Magic lantern installed so I could shoot at 320ISO. I used a combination of 45W and 85W CFLs inside the umbrellas. I think it would have been better with more wattage in softboxes. Note, also, you light the greenscreen separate from the model - there is some light spill from the green screen lighting that actually made keying the footage easier, but it wasn't necessarily desirable.
$200 isn't much for lighting. Sorry. I could do DIY lighting in that price range, but you will need to make your own equipment. The CFL bulbs alone can run $200. Some places to check: