I paid 300 bones for one. Seen only a few advertised here and there, and that seems to be about right; a bit more than a regular Tokarev, but still a very cheap pistol. If you don't even have a full magazine of adapters, I wouldn't hold out hope for more than that.
It works very well, and it's fun to shoot .22LR from a TT, but annoying to chase the adapters down all the way across the range floor. (I've got Toks in three calibres now.) Seems they were brought in to the surplus chain in Canada maybe 15-20 years ago? They're out there, sitting in people's safes.
Got an ad. in the EE looking for more of those chamber inserts. I'd offer to buy yours, but then it'd be impossible to sell the gun!