anywhere in between 1500(for garbage bin discs) to 5000 for a (almost) new set of discs.. These retail at 4200 each.....
I believe there is a company in Germany(or Switzerland, not really sure) that can re-surface the CCM discs, which will be far cheaper then buying new discs..
Be aware you officially also need the ceramic calipers(different dust seals due to the higher braking temp with CCM discs) and ceramic brake pads