The Eventorbot! open source 3D printer has a simple design requiring fewer materials than most other 3D printers. The frame is made from a single 4′ long, 2 1/2″ square tube (14 gauge/1.5mm/.0598″ thick; cost: less then $20). With this design there are fewer plastic parts and a stronger structure, all wires are hidden, and the unit has a more appealing, finished look.

Links to download plans: http://www.thingiverse.com/thing:28915 http://www.reprap.org/wiki/Eventorbot

Tutorial videos: http://www.youtube.com/user/eventorbot