Like I said, this doesn't get much easier and it's cheap.
1 - CD or DVD. This is something you can make with those old scratched up discs.
1 - Dollar Store vibrating toothbrush.
1 - Package of Markers.
1 - Hot glue
You will also need a drill and drill bit to make the holes. The size of drill bit depends on the diameter of the markers. The markers that I used are 3/8" in diameter