Eek! That price tag, and the fact he is promoting his own book, would send me running for the exit.
I believe both peptide and stem cell therapies for knees are still in very early stages. Benefits are being shown, but still more to be learned about who benefits, and at exactly what stage of deterioration.
If you really want to try it, maybe you can search for a clinical trial being run by a teaching hospital or university research facility. Your doctors would be a good place to start rather than an internet-based promoter.
Are you thinking of asking your provider?
Sue