Mod idea for extra trading possibilities

I have had this idea for a while but I can’t mod and I don’t have enough free time

-give every hearthling a specific amount of money that they can gain and loose during trade
-only be able to suggest what they could buy not directly control
-in order to get items from other crafters for their crafts hearthlings have to use their own money to buy crafts
-if a hearthling has run out of money you could give them money from the town treasury and if they have too much money you could tax them
-there will also be inter town trading so one town member could trade to another town member