In Bulgaria in the last 5 years there has been a spike in the price of commemorative coins / coins in general - this coin is just one example of wider trend in Bulgarian Numismatics
More and more people are buying coins like this as an investment and as such are driving the prices up .
Another factor is that before you could buy Socialist Era commemorative coins from the Bank (BNB ) for a relatively low price ( usually just the precious metal content value and some premium ) , but in the last 2-3 years these stockpiles have finally run dry .
This has led to prices increasing since there is no longer the Bank to offer a cheap alternative .
In this particular case- which is a prime example , in the 2019 Catalogue issued by the Sofia Numismatic Society , It says that these coins could be bought from the Bank (BNB )for just 40.8 Leva .
I don't have the 2020 or 2021 catalogue , but in the 2022 catalogue ( same issuer ) the coin has been depleted in the bank reserves , and now trades for 200 leva - a 5 fold increase in 3 years . And that is just the price in the catalogue , which , given the auction results posted , It may have been undervalued .And the value keep going up
