its not too expensive. My 1000watt hps runs like 25$ a month, but if u want superior grow u should look into an Eye Hortilux bulb, it combines the red and blue spectrum. Very noticeable difference from a standard hps bulb! and there isnt even a difference in my bill, and my 400 MH is on 24/0, whiile the hps is on 12/12.