Affordable micromotor for jewelry
"usable" is relative.  I bought a perfectly functioning dremel-like tool off of AliExpress for under $30 and it came with bits for the activities you describe above, as well as a 3ft flexible shaft attachment.  It took weeks to get to me but works great, however I am constantly aware that if it should break, I'd be on my own.  Overseas support lines are beyond my patience threshold.

This is not an endorsement.  I'm not even providing a product name or a link.  Just offering a source for what you are looking for and testimony about my own personal experience with that tool.