digital ballasts....

i just got a 600 mh/hps digital. do you need to use a high end power bar to filter the power? The guy at my shop say you can fuck up you ballast with unfiltered power. has anyone heard of this before?

I haven't heard of it before.
I did fry my timers though when trying to use my 400 hps without a light controller to control the surge when i first got it.
If hes saying that a your ballast gives out a large kick each time it powers on he may well be telling the truth.

how much do they run $. do I need one?

Well i dunno if this is the same thing or even what you need.
Best to talk to someone with more exp in American voltages and setups as i am english.
Heres a link to what i am talking about though.

http://www.greenshorticulture.co.uk/details.asp?productid=555&subcat=287&cat=182

its a good idea to have one of those, i have a belkin that cost about 40 bucks that i connect all my fans and stuff i want running with the lights on but you could probably do just fine without one, lots of people dont use one but i would if the light shares a circuit with other stuff in your house