I agree with the ebay thing ... I bought 2 lights from this guy topdogseller and have had no problems with them .... here is a link to the 48" 216 watt setup i bought.
http://cgi.ebay.com/48-4-ft-T5-Light...item19befce081
The lights work great, so far ... you get what you pay for indeed .. but these are actually not to bad at all, and a few hundred cheaper then others of comparable bulb/wattage. Good luck.