Well, this depends on how you wanna find your talent.
If you go by the way of Agency..it's gonna be pricey. Whether you want Union or not.
Now, you can put a call out on the usuals..Craig's, Monster, Tribe, etc..But that means you're gonna have to sift through alot of ....let's say..novices.
How long is this thing? How many pages? How many lines? What kind of character voices? How many characters?
All these things will come into the price. Do you have a studio? What are the time constraints? and so on.
Most vo talent go by the hour..like myself. But if you offer a flat rate..to the individual or agency..(plus 20% for the agency's fee) it can be done cheaper. If you're gonna go commercial..you're gonna need real talent..not some hacks that think they can give good voice.
So, you'll need to pay for those talents. But, since its a starter and new..you won't have to go nuts on the budget for voice.
If you think one voice will only need two hours..without going through an agency..I would say 500 bucks. With an agency..500 plus the 20% tacked on. Thats just off the top of me 'ead.

v

What type of voices are you loking for? I am a novice (as far as paid experience) but I've been doing voices for years (teaching, daycare, ect.). It was not until last year that I was approached by a professional who encouraged me to pursure the field. I'd mention his name but I gave my word not to (but he still plays Vegas every winter if that helps). I am eager and I don't wwork with an agent as of yet so pay negotiable as long as you can set up a recording studio in my area (N.E. Utah/S.E. Idaho) which would probably be less expensive that in LA. Feel free to contact me at woof8616@aol.com to discuss the matter further.