The best I can make with Polymer clay is snails and snowmen so I'm pretty much in awe of people who can sculpt tiny detailed pieces like these awesome Tom Servo and Crow T. Robot charms. The Clay Collection sells these little guys as well as a Gypsy and Satellite of Love charm, and as she explains in her store profile:
"You can consider any piece from a set of earrings as a charm individually. It can be mixed and matched, made into a pin, a ring, put onto cuff links or a key chain, combined with other charms to be put on a charm bracelet, used as a cell phone, purse or zipper charm or can be strung on a chain for a necklace."
The pair of earrings sells for $12 and a set of all four Mystery Science Theater 3000 themed pieces that can be used as wine glass charms is $20. (Wine glass charms also make excellent knitting stitch markers!). If you're a child of the 80's you'll definately get a kick out of browsing around The Clay Collection which also features lots of great video game and memorabilia related charms.