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.
I have an FDM (filament deposit) printer I built that can do 6" x 6" x 6" and even that's extremely restrictive.
Plus if I want to make things in metal I have to use "lost PLA" casting which involves depositing plastic filament to make a part, then using the part to make a plaster mold, burning the part out, and molding the metal.
I think the real future of 3D printing for structural/functional parts is Selective Laser Sintering (SLS) which is the same idea as the Peachy but with metal powder rather than liquid resin and won't reach consumer price points for a couple more years.
I'm using a RUMBA baord, so theoretically I could do a triple extruder if the software supports. I have a machine shop, so I could make my own hot head parts to make it compact and lower mass with 3 Bowden extruders.
I'm in the middle of building a Rostock Max and I should be finishing it this weekend. It's another delta design with a HUGE build volume (11" diameter and 13" tall). As it is currently configured it will run PLA and ABS, but will be upgrading the hotend once I get everything configured and running good so that I can make truly functional parts out of Nylon.
There are several companies in Tucson of all places that are solely dedicated to manufacturing parts using additive techniques. They have an entire manufacturing line that is filled only with these types of machines.
The Form1 will have nice resolution, but it's still SLA, so the resin is fragile. Good for show and tell...
The patents for FDM expired in 2009, which is why you see so much growth with the open source printers. The patents for SLA/SLS expire in 2014! So hopefully we see a lot of growth there as well.