Yea ike hemp goddess said you need a little more light for 3 plants if you want to see any good results.
But if your just vegging 100 watt hps will be ok for 3 plants. Are you flowering outside if so youll be ok. but if you plan on flowering under lights you will need at least 20,000 lumens to get good buds. The 400 watt hps you can get for $100 has 55,000 lumens.
You can get like 20,000 lumens of CFL's for like $50-$75 bucks but your set up might look abit haggard
10- 2000 lumen cfl's $20
5- light socket splitters $10
5- Cheap lamps or light fixtures $20.-------------20,000 lumens
where do you get 10 @ cfl for $20....I baught mine 2700 lumes @ $10 each...that would be $100 right there. indoorsun.com has the 400 for $100. I did build a Male chamber with CFL and know that a 400 would have been cheaper but wanted to go this route..I can still change it out..
I use HD for Veg ( blue spectrum light) and yes I read it increases the odds of a female...and HPS for flower ( red spectum ) for tight bud formation..
Good luck keep us posted..but most of all KEEP M GREEN