Deneane Hart has very kindly compiled this comparison of the various dog discs available on the market for the community. Obviously, prices are current as of May 2016, and are subject to change. They also do not include any quantity discounts that may be available, so discs purchased through the club will be different prices. The discs that are grayed out on the spreadsheet are not currently available. Click on the link to view the spreadsheet.
Thanks Deneane, for this cool resource!