The stuff I've used in the past came from a rock tumbling kit we bought the kids a while back. Rocktumbler.com is the one I think we used. I don't know how prices compare though. That might be another avenue if you need it.
Thanks everyone. MTBob it now shows delivery by this Friday. Weird...I think I'm either losing it or Amazon is playing games. Neither would surprise me.
Bruce, since I have Prime, I went ahead and ordered from Amazon. But I will bookmark The Science Company for the future.