Many of the gun building suppliers have some very nice blanks already cut to somewhat resemble a rifle. I find most of the prices fair but once you tack on the shipping it becomes expensive.
I use a couple different local wood suppliers - not like home depot, but specialty wood places. I prefer that because you get to touch/feel and select the exact (board) that you want.
I have found I can get two full stock blanks OR a full stock and two half stock blanks out of a single board if I get a piece of 8/4 or 10/4, 9-10" wide and 5' long (which is roughly 7-8 board feet) often for about 60 to 80 bucks (for curly red maple dependent on the amount of curl - the cost goes up by 25% if I want sugar maple and almost doubles for figured walnut).
In comparison, Track of the Wolf wants over 100 bucks for a single curly maple full stock blank and it would run you a further 40 to 60 bucks for shipping (depending where you are).
So if you can find a local source of specialty woods - have a band saw of a jig saw (and patience), I would source my own wood - save you a bundle.
I have just cut up a piece that cost me $63 that yielded a Maryland full stock (42" barrel) and a Hawken full stock (34" barrel - yes Fred, I'm getting it cut) - and it's a super curly piece of wood. 30'ish dollars a blank is about a cost effective as you can get unless you grow it yourself