“Roll to see if you know the leech-to-gold exchange rate.”
Hey, find a medicine man and you can actually get some good trade for those.
Apparently even today still, IIRC leaches actually do get used for legitimate medicinal purposes in the modern day. Them and maggots, I believe for cleaning out necrotic flesh.
You find three goblins in a trenchcoat with a shack full of dubiously acquired merchandise of poor quality. They’ll buy your loot for 12 silver, a shiny button, and this really cool bug they found yesterday.
If they promise to be my new best friend they can keep the silver
Sure be a shame if all that selling screwed up the economy enough to completely offset any gains of collecting everything they can carry and immediately sell it instead of, y’know, roleplaying how actual people in that world would behave.
I think my next campaign needs a pawn shop that’ll consider buying anything but will seriously low-ball it if they can’t move it easily. And maybe need to talk to an expert they know.
Maybe like this
Or you find this guy
“I can give you 50 gold, after that we’ll need to get the weights and measures out to trade goods. Don’t worry, I don’t cheat my scales.”
If you’re gonna do that, you can’t just have it be a normal shop! There’s got to be consequences:
https://tvtropes.org/pmwiki/pmwiki.php/Main/TheLittleShopThatWasntThereYesterday
Alternatively, for a shop to be economically viable in the middle of a swamp, it needs to be one of those tourist traps with kitschy signs all over the place for miles around.
They need to unload their diseased rat livers somewhere!