Okay, so, I think #2 here will give you a headache. "I want the main motivation be about money... but I don't wanna deal with money," isn't the best approach to compelling content.
I disagree, for the same reason you said that I don't need to know the exact amount of GP for a fur pelt.
The worth of a pound of cocoa beans doesn't matter. The cost is quite far down the road when cocoa beans haven't been discovered yet. The process of "discover, plant, grow, harvest, box, ship" is quite a long one before the actual value even enters the equation.
The point is, "we desire to harvest as much resources from the place as possible." The PCs won't be encountering the price of goods, or be involved in the collection of those goods. It's purely the motivation that is pushing expansion, the tenor of relations, and the source of friction.
Similar to how, if the PCs are the crew on a merchant vessel, the cargo in the hold doesn't have much of an impact on the story if the point is to have the PCs become shipwrecked. Or hit by pirates (as pirates don't know what you're hauling till they raid your hold).
You are playing D&D here? Their technology is not the issue. Stone knives and bearskins are fine. In D&D, most of the damage comes out of the class, not the weapons. A couple druids or clerics of the native's gods with some barbarians to back them up could seriously mess up a town, if they were so motivated. And they have a continent full of them, while the settlement only has whatever they brought with them....
Then replace technology with magic or whatever word represents "potential for success in physical conflicts". The natives ain't up to a fight.
Hm. Sounds like you've created your own problem there,
and I'm not sure about the idea that the natives will sit by while this goes on, but those are aside the point. Let us say the natives don't give a hoot about the loot. So...
Rather than contort yourself trying to figure out how to work normal economic function in a place that lacks it... just don't. Accept the thing you built, and its natural results. They will not be able to easily convert one form of wealth to another.
Also, recognize that in the end there's no real difference between "give them random magic, and allow them to trade that in for what they want" and "just give them what they want in the first place". Makng them jump through a hoop to get stuff they like is not really a value-add, so to speak.
It's not normal economic function, it's
D&D economic function. It's that there's no in-game use for gold past 10gp except buying magic items.
Forcing in ways to buy/sell magical items is vexing (especially since I personally hate the idea of buying/selling magic). Not forcing ways means I need an exact Christmas list the PCs want, and they just Conveniently discover that precise thing in the next place they look. Which feels quite contrived.
Every option is annoying. And that's all it is. Not a
problem, just a choice I don't like.
Ultimately I've decided what I'm going to do: no buying and selling, ask for item
suggestions, players get what they get have to live with it. Now all that's left is simply replying to comments in the thread.
You'v epositioned it so that the PCs are unlikely to have anything the natives want, and have discarded teh idea of the PCs doign favors with the natives. Maybe just remove the natives as irrelevant? It is a continent full of monsters and beasts, and the ruins of a civilization that died....
This also gets you out of the bad look of re-enacting imperialistic oppression of natives... They just aren't there to oppress!
No, absolutely not. Interaction with the natives is half the fun to me. The culture and interaction and so on. Hell, the story won't even matter without the natives.