The DIYLILCNC is a fully functional, open source 3-axis CNC that you can build with basic tools and parts that can be locally sourced. The idea is that you develop a 3D design in a CAD application, put feedstock into the CNC, and print your design to it, and it cuts and grinds away everything but what your design is supposed to be. Total cost of construction is about $700us. You can download the plans and DXF template files from the website for free (they have a CC-BY-SA license).

The Shapeoko is an open source CNC that you can either buy as a kit or build yourself for about $300us. Work up your design on a laptop using open source CAD software, clamp feedstock on the bed, and it'll produce what you designed. Because it's open source it's not limited to wood - it could be adapted to just about any material that you can cut or grind could be. Chances are, someone's already done it and posted the docs.

Everything is also kept in a respository on Github: https://github.com/shapeoko/shapeoko