As well as working on my Arduino based "start here" robot with cheap geared DC motors, I've been planning out where I want to go next, and have been reading up on stepper motors. This seems like a cheap option for experimentation:
An informative controller card with a detachable, small, 7.5 degree stepper for just over ten dollars. A couple of these might make a more robust motor system for my starter 'bot. Anybody used these?