costs a hundred or two from scratch depending on what you already have... CFLs range from 4-10 bucks a bulb, depending on the wattage you get, 42w are around 10 bucks... you'll need a box or an area that's lightproof... you'll need good duct tape, white paint, light fixtures, fans, at least 1 surge protector, air filter (kill 2 birds with 1 stone at home depot... activated charcoal FAN filters, buy 1 get 1 free... it's a FAN that's a FILTER...), some way of blocking light from coming in those fans, soil, nutrients, and pots, although you probably don't have to buy the pots... people throw away buckets and bins and pots every day... you can actually dumpster dive for a lot of the crap you need... sometimes you can even find a perfect cabinet for a box...