I started building my own CNC this past winter and I'm about 80% complete. So far I've spent about $250 on hardware. This is based off the JGRO design, found on CNCZone.com, and expanded to make the cutting bed 24x36.
(3) Stepper Motors - $5 ea = $15
(3) Motor connectors - $.50 ea = $3 (w/ ship)
(1) Hobby CNC EZ controller - $70 (w/ship)
(1) 6' straight-thru serial cable - $25 (can you believe that?)
(1) sheet 3/4" MDF - $28
(1) sheet 1/2" MDF - $22
(1) 4' steel angle - $15
(3) set of skate bearings - $2 ea = $7 (w/ ship)
(6) 1/2" bearings - $1.50 ea = $9
(2) 1/2 - 10 Acme leadscrew - $10 ea = $27 (w/ ship)
(12) Acme nuts - $1.50 ea = $22 (w/ship)
Misc. nuts and bolts = $25
Total spent so far is $268
There are a few items I still need to get such as couplers and anti-backlash nuts (another $115

), but basically it's all there. I'm using some demo and freeware software at the moment, although I do own a license of autocad.
I'll post pics soon. If anyone wants more info I'm more than happy to help.
Gyv