That strikes me as a very reasonable cost. Annualized inflation since 1936 to today has been 3.52%, resulting in that $300 expense being today's equivalent of $5,662.
Fun research project (@commems, are you listening?
) ... what does a 'typical' modern commemorative coin sponsor pay for die design/engraving costs?
I wonder what happens to the master die at the conclusion of the coins mintage program? Since the sponsoring organization paid for it they have some standing to claim possession and preservation.
Then again, the Mint likely also claims possession due to the legal tender status of the potential additional coins struck.
My conjecture is that the mint retains and eventually defaces the master dies, otherwise if released to private ownership we would over time see a few appear on the secondary market and, heaven forbid, occasional restrikes in latter years.
Take a look at my other hobby ... http://www.jk-dk.art
Too many hobbies .... too much work .... not enough time.