Iver-On only coast me about $25. from Jeffers, and it's supposed to work on worms as well as mites and lice, and stuff like that. I've had bad experiences also with Ivermectin paste, and I've used Revolution for Puppies and Kittens, but that's really hard to apply in the correct amount, plus it's way, way too expensive. I just finished a full round of treatments for teh cages that were affected and it appears to have worked well with no noticeable side effects. The meece were annoyed bit by the wet patch on their back, but that was the only downside. I gave them treats after each treatment so they wouldn't try to lick it off each other.
I've used Sevin powder in the past, but I believe the Iver-On is a better option. It's a lot of work powdering each mousie and brushing it through the fur thoroughly. Some of the meeces seem to really enjoy the brushing, though.