Yeah, it is a little expensive. The price depends on what you are looking for. The setup for the motorized kit is for a life time and it is heavy duty. Plus if you are a nut, like the guy at the end of the page, you get your max rpms to be only 60. My K10 grinder does 300 rpms but is a lot more expensive

Maybe a motorized screwdriver with a rubber band.
Cheers