There must have been something much earlier...
nostr:nprofile1qqsvrlrhw86l5sv06wkyjgs6rrcekskvk7nx8k50qn9m7mqgeqxjpvgpzdmhxue69uhhqatjwpkx2urpvuhx2ue0tc48yt did diagon alley make a real trade?
Discussion
plebeian.market might have facilitated something as well but I'm not sure when they made the migration over to Nostr...