Daniel of Tinkernut has refashioned a 3D printing pen to make a 3D printer for under $100. The project involves getting the pen to communicate with a CNC machine, and switching the pen off and on using an Arduino. Detailed directions are available in Tinkernut's YouTube video. This is a great project for people itching for a 3D printer who don't have the funds to purchase one at present. Read more at 3DPrint.com: http://3dprint.com/105764/make-3d-printer-from-pen