disregard that link,for some reason i cant edit the post.
Anyways,if you really want to save some money,you should check out some of the DIY retros.A 250w M58 ballast,reflector,socket can be bought for $90.A 2x54w
T5 retro is only $110.Add a pair of MH bulbs for about $120 and your only at $410.Throw in a couple 4"fans and that'll bring it to about $450