I propose a prize of 1 satoshi.  Or 9 satoshis.  Or if rarity is exponential, 2⁹ satoshis; if my long-term price predictions are correct, that could someday be worth anywhere from about 5 to 50 of today’s dollars!  Of course, delivery of the dust prize would require Lightning Network or other offchain transfer.

Anything more seems excessive for what I infer to have been effectually a lottery winner who bought a random fake NFT for fake bitcoins, in a fake system that was created as a joke.