If you can find one, it will run a good piece of change because they are so rare. The only legal source is zoo aviaries that had a bird die and this is neither a common species nor a common occurance for a zoo's birds. Expect to pay somewhere between $2500 and $4,000 possibly more for a full skin. sinlge feathers are being sold for $25.00 to $100.00 each. Personally, I will not pay that kind of money for a bird skin.
Remember that even the old masters such as Kelson, Hardy, Hale, Blacker, Price-Tannat, and Maxwell regulary subsituted Kingfisher for Chatterer (Cotinga) and spoke of doing so in their books because of how hard it was to get Chatterer and how expensive it was even then.
Use Kingfisher or better yet African Roller to substitute for Chatterer (Continga). You can also use small withe duck feathers or the white feathers from a Chinese Pheasant dyes Kingfisher Blue. Personally, I use African Roller because it has more of the desirable florescent-like blue feathers than the Kingfisher. Kingfisher is around $25.00 per skin and African Roller is about $35.00 per skin give or take a few dollars. This is far better than what a Cotinga skin is selling for provided you can find one.