Online through any hydro store. Not going to be much of a difference from one site to the next. Take 5 mins to shop around and get a deal. Go with a 250hps if you can. Cost you around 2hundred. 150hps under 1hundred. my hydro guy here ships me all the time at good prices. I think anything over 25.00 is free shipping. Hydro Terra -Hydroponics Indoor Gardening,Hydroponics Supplies,Hydroponic Systems, Nutrients and Grow lights -- guy is legit and has become a personal friend. Tell him you saw his ad on craigslist and he will give you like 15% off your purchase. Peace