upgrading to disc brakes

prolly like $100-$150 i would think, like 70 for each 7 and like 50 for each 5, also rotors make a difference

I kinda priced it out in my head because I was considering doing the same thing. You'd need a front wheel ~$60, avid bb7 ~$40 and rotor ~$20. About $120 to do just the front.

I opted to just get the rockhopper disc for $100 more.

ya true, he would only need the hub though, lx or deore like $20 and re-lace it

I bought a '05 RH base. After a season of riding I upgraded to Juicy 5 disc brakes. The upgrade cost me $200; pretty much just for the brakes.
I bought disc ready wheels (used) online and sold the stock ones at the same price. Same goes for the shifters.

I just bought a full BB7 combo kit for $176 (that's rotors, calipers, pads, cables, and levers).

Of course you could keep the old levers - so there's $ saved.

$200 sounds like a good bet...