Market
Each level brings one more merchant, and each merchant carries 1000 units.
As the sun climbs, the stalls go up, the scale pans ring, and merchants from distant lands unload their dusty packs. Haggling in the market is an art: half an hour of talk over a bag of salt, and then both sides part believing they have won.
The market's merchants send the holding's caravans on their way. They sell what is spare and bring what is lacking; they are the blood that runs in the kingdom's veins.