Build a 3d printer yourself. Check out reprap, you should be able to get a decent one together for $500USD. It will likely even cost less if you cannibalize some robotics parts =)http://reprap.org/
The accuracy of a reprap is as good as you decide to make it. The hardness of the materials depends on what you use, but ABS plastic is one of the common ones and it is pretty sturdy. I wouldn't imagine you'd want to use printed abs gears for a long time in a bot, but for prototyping and development it is awesome.
reprap made gears...they aren't perfect, but they workRepRap making gears
I am building a reprap right now after seeing them in action at a few of nerd conferences I've been to lately. One other bit about the reprap, it is to some extent a self reproducing machine - that's the idea anyways. People have been building them with tighter and tighter tolerances as they continue to rebuild their machine using parts it creates!