There are many low-cost 3D printers on the market right now. My Printrbot Jr (kit) cost me $400. Having said that, I've spent several hundred dollars upgrading it (heated bed, extending the z-axis, improved belt system, etc.).
The Peachy is impressive in that its extremely simple mechanism and audio-based drive cuts the cost down to just $100, but from what I've seen, it's capabilities are pretty limited. Particularly when it comes to part size as addertooth says.
My PB Jr can print 4" x 5.5" x 7" and I often struggle to fit parts in to that envelope.