Mice are intelligent, active pets that are fun to entertain very inexpensively. Virtually anything that is safe for them can become a toy. They require exercise and stimulation for their health--and being chased around by the cat doesn't count. Pet mice enjoy chewing, climbing, hiding and running. You can create some fun, easy and inexpensive toys for your mice using stuff you probably already have around the house.
Put 1 or 2 tbs. of cornstarch in a small glass jar or coffee mug. Place it in the cage on its side. Your mice will wash themselves with the cornstarch. They love taking dry baths.
Hang a piece of sisal or other natural fiber rope or thick cording from the top of the cage. Mice love to play and climb on hanging ropes. Remove and clean or replace it if you suspect that your mouse may have urinated on the rope.
Place some clean sand or kitty litter in a small box. Bury some mouse treats in the sand or litter and set the box in the cage. Your mouse will have a wonderful time digging for buried treasure.
Place several hollow plastic cat balls that have bells in them into the cage. Your mouse will love picking them up, pushing and carrying them around, and generally remodeling the cage with the toys. Make sure that these are hard plastic, and not rubber. Rubber bits can be swallowed and end up causing intestinal blockages.
Place some mouse treats in the center of an empty toilet paper roll, and secure them into place by stuffing some tissues or paper towels in the ends of the tube. Poke a hole in the center of the roll with a sharp object to allow the smell of the treats to attract your mouse to the toy's charms. The mouse will love not only the treats, but using the tube as a tunnel and then shredding the paper and the empty tube, as well.
Put some chew toys into the cage. Give the mice a steady supply of chewables, which are necessary for their dental health. These can be all sorts of dog chews, including rawhide. Any untreated wood items are excellent chew toys, too. Paper and cardboard products for chewing and shredding are a must. Boxes, empty paper towel and toilet paper rolls, wadded up balls of newspaper, cardboard egg cartons and similar items are accepted and will be destroyed with enthusiasm.