>>4What model?
I've seen kits sold for $350 or so.
Also, I reckon some delta bots may be cheaper than cartesian bots.
GUS Simpson looks ridiculously cheap, but it's experimental and cannot currently self-reproduce.
Also, I think it's more practical to build something that have kits available.
http://www.youtube.com/watch?v=IEGTe1G2Gqs