My $35 ball spinner.

Variable speed polisher sander from Harbor freight. $29
A 6 gallon pail from my work... uhmmmm - free
nuts and washers from the $3.00
Flow pot from Walmart $2.00

The polisher says 200 rpm to 3377 rpm. I'm not sure if the slow speed is 200 but i think it needs to be slower so I might go get a potentiometer from Radio shack and wire it in there. I also need to do something with the base of the polisher. It works fine but I would like it to be a little more stable at higher speeds. The tub hits the side of the pail a little bit. I think I will get some longer bolts and extend the bolts that hold the handle so that they go through the outside of the pail.
Might need some larger washers for a more sturdy base for the tub also. For a first try and just throwing it together is works awesome.