i'm looking to try my hand at growing. i really don't have the room/time/experience to grow more than about 3 plants.. so i'm wondering what wattage of lights i need for that many plants? i'm going to start with the cheapest way possible.. probably find some HPS lights on good old Craigslist. i'm going to buy a plant ready to flower.. so no veg period for me. in that case, do i need a ballast? forgive me if i sound dumb, i'm a newbie!