Gander Moutain in Flint (check other stores) has the "Ice Buster" the yellow sponge ones ya can cut to length and use as a slip bobber with your spinning reels. They also have the Thill wooden bobbers, slip/stationary.
I personally hardly ever use bobbers anymore, but I do use the "Ice busters" when fishin' for Crappie with minnows. The equipment available now-a-days makes bobber fishin' almost obsolete (unless ya need a completely still presentation). IMO, line watchin', rod tip watchin', and a quality rod/reel with good "feel" will ice ya more fish.