Saw someone mention accounting so I'll throw this out there, the original purchase price plus any other costs would be the value of the Varkon game as inventory. The price a third party would be willing to pay would be considered the fair value (probably a level 3 given the limited observable data we have to go on). If J0n sold the game, he would have to evaluate from a ASC 606 perspective whether the transaction was a valid sale (his concern about collectibility may push it to be deferred revenue). If J0n concluded he did in fact believe he would collect and it was a valid sale but the payment was later reversed then he would record bad debt expense of the outstanding receivable. If not, he would recognize the loss of inventory value. This is all GAAP accounting as tax accounting is a whole different animal. Ah, good old ASC 606, always fun to bring up a party.
My comments normally kill discussions so if this works, you are all welcome.