$500 will get you a 600w COOLTUBE digital setup off of ebay from the seller POWERKINGSHOP, along with a 2x4x5 grow tent for $90, get at least a 400cfm inline duct fan, 25' of ducting, two 4" 80cfm duct fans from HTG, n some 3gal growbags, a couple bags of Fox Farm Ocean forest soil, and the Fox Farm trio of nutrients. As for seeds, your gonna need to budget for those, but thats the easiest part. You should come in right around $500 for your entire setup. If you have cash to spare, you can get a PPM meter for $30 off ebay, and you can get a Ph meter for the same price too.
Dont skimp on the quality of your equipment. Having equipment that wont break down when you need it the most is invalueable. If thats your budget, you should be able to pull off a nice 10 plant grow with it. You will be able to pull off some SERIOUS fuckin nuggets & weight if your patient. N then after that, upgrade the shit out of everything
-- you already have a 150w light, so youll already be on your way to setting yourself up for a perpetual grow in the 3rd n 4th time around. That 150w will be awesome for a clone army.
good luck, n i hope that helped
-K1.