Sounds like between the lines he's saying he can't afford a bunch of stuff.
If you are thinking you can run that 400w bulb without a ballast, just plug it into a lamp socket you're wrong.
You can start with a couple of these for $20 ea though if you can't afford much, and yes hpw will work for veg if that's all you have. In fact they'll veg pretty darn fast compared to normal flouro veg setups.
Anyway open this link twice for the $20 lights:
http://www.e-conolight.com/Product/EProductDetail.asp?ProductFamilyID=7&FGNumber=E-MT6H151G
~$54 will get you two of those shipped and that's enough to start growing with. It'll give you 30k lumens, equal to 20 or so small cfl's in light output. Enough light for about 5.5 sq feet of grow area which might not seem like much but you could grow like this:
http://www.icmag.com/ic/showthread.php?t=88449
Doing clones that way turn around time is fast, hardly need much veg time, but to use a dedicated flower chamber and flip clones eventually you'll have to find other lights for a veg area because long term I'd reccomend keeping both the hps's in the flowering area like everyone else would. At the $20 price it might not be bad to just buy three of those and dedicate one to veg even though hps supposedly isn't ideal for that. It will work and tt's just too cheap not to use one.