I recently decided to try to build a small CNC router. There is a lot of information online for this, but I settled on the Mantis 9. It is a desktop (footprint is 10"x10") unit; the largest workpiece it can handle is about 4"x6". It was easy to build and the cost was around $100. This machine is controlled by an Arduino microprocessor, and connects to a computer's USB port. Good information can be found at these sites and elsewhere:
Here is a picture of my CNC-
and here are some of the things I've been making with it--
|Note the 4-bar linkage used as a hinge.|
A whirligig- Click on the image to watch it in action.