I think I will settle with 150watts hps
Don't waste your money on a 150-watt and I would say don't get a 250-watt either. You will get very little light penetration from a 150-watt or a 250-watt HID light. Very often growers new to HID lighting will WAY overestimate the capabilities of a lower wattage HID light and before long be very sorry about their choice.
Go to 400-watts minimum or else you will only end up spending more on lighting in the long run because you will soon realize you need more light and then end up paying for another lighting system and the two together will add up to a bunch more than just buying the right, or at least the better light the first time.
Even if you had to skimp and purchase the HTGS 400-watt with magnetic ballast and have to run a MH conversion bulb for veg you would be much better off than going with a 150-watt, or a 250-watt.
$229.95 will get you a Digital Greenhouse digital ballast 400-watt light that burns both MH and HPS bulbs ... that is not a bad price at all for a pretty decent light.
Save a little more for a little longer time if you have to and purchase a good light. Later you will be very happy that you did.