[ravenfish]

It's worth noting that the generic dungeon fantasy setting is sufficiently inspired by medieval Europe that the economy is probably guild-based. The guilds apparently allow delvers to sell found items without issue, but, if the PCs seem to be moving out of the "delver" role and into "full-blown merchant" role (without having secured appropriate guild membership), them, if some stern warnings don't suffice, they will rapidly find themselves disbarred from the legitimate economy.