Yes I have an idea:

Suggestion: Economics

I’ve talked to CallieMav and Ma_c_hi about this, and they’ve both started testing various aspects about it.

We already have the ability to sell custom items through villagers, which we can input into this idea like so:

Player buys a custom item from a villager using (ex. iron ingot) and then takes that item and sells it to a sign shop for actual $$$?

If what I just said makes no sense disregard it, but don’t disregard the whole idea. To answer your earlier reply, we do not need 3 different worlds because we can simply use custom-named items not-obtainable through vanilla MC activities and only can be bought/sold using the NPC Shop System.

P.S. – The new shop system with chests should make it much easier to be able to sell these items, the only thing Ma_c_hi and CallieMav and I have been having trouble with is making items non-teleportable.