Lighting Help Question Please

Hi Everyone, I'm a newbie with a simple question regarding 400watt High Pressure Sodium and Metal Halide lights. If were to get a ballast for each of those two lights, would a 400watt ballast be sufficient or would I need to up the anty? I am new to this and so general pointers would really help me! I also don't want to break the wallet getting the lamp and ballast so would cheap ones, say $20 for the lamp and $60 for the ballast from ebay, be alright? Where would the best place to get the two be based on more experienced experiences from members? This will really help me, thank you soo much in advance. Anything else I should know about lighting and ballast and lamps would really help me out !

im super stoned right now but I will take a crack at it. From my understanding and recent shopping around...one ballast to one light, I've found a dual ballast which would run 2 lights. You can get a switchable ballast to use with HPS and MH. Reconsider the ebay idea, you don't know what you are buying or if it will last. You don't want a ballast going out on you mid grow you will be pissssed!
Buy from a local hydro shop, taking stuff back is easy if needed plus you get a warranty. I got a 1000w for a 150 buks to give you an idea. Plus shit is expansive in california. Oh and definitely go MAGNETIC and not digital. They're built to last.

Can't buy used lol. Bulbs reflectors get beat up quick.

First light I ever used was 400 hydro farm built in ballast. Great for veg but need 1000 to grow thick nugs

is ideal ..http://www.amazon.com/Apollo-Horticulture-Dimmable-Detachable-Reflector/dp/B00547I5I8/ref=pd_sbs_lg_6

Thanks for the wonderful responses. That last response in the link above seems pretty dam good, I don't think I can beat it. Although I do have to ask, and I might sound really stupid asking this, but would a T8 fluorescent that consumes only like 30 watts that supposly has a high lumen rating from the local hardware store be nowhere as good as say a 400watt Metal Halide lamp like in the link above?

The Apollo is a good value. I've been using my 600 for over a year and it's worked great. Fluorescent lighting doesn't have the penetration you need. That being said, people do use them and I've seen good results but right now HID is the gold standard.
If you get t8/t5's you can always use them for side/supplemental lighting. You'll be happy with the Apollo.
One caveat - the ballast fans are relatively noisy, at least on mine. There are not silent, at any rate. Just an FYI.

Thanks, I want the gold standard. Would it be alright to use the Apollo throughout the entire grow process, from vegetation to flowering? Or should I really try to get a Metal Halide and a High Pressure Sodium for each of the two growing phases? Thank once again for the input !

O just another thing, when purchasing the Apollo, what else would be strongely suggested to get also, if anything? Thanks the help is greatly appreciated !

Well what I would want to do is get the Apollo above, and then what im unsure of is if I get a 400 watt high pressure sodium bulp if that ballast would work fine for me for the rest of the flowering stage of the plant's growth