Money
A silver piece ($1) represents one day of unskilled labor & is the smallest denomination of coin in circulation. Most things are paid for with debt Debt, typically via the gift economy. An asset’s price in $ is said to be its Value.
The Gift Economy
You are gifted what you need today, expecting that tomorrow you will return the favor. Not doing so is dishonorable. Coincidentally, travelers & transients are dishonorable because you cannot ever hold them to a promise the way you & your village can hold your neighbor to account. If you need to track a debt explicitly, use the Debt system.
Converting from Other Systems
The best way to convert prices from other game systems’ price lists is to find the daily labor-value & convert based on that ratio. Be warned that many game designers have little grasp on finance or economics & that their assumptions may not hold steady across systems or settings.
The Marketplace
The vast majority of the economics rules are found in the Marketplace chapter. It’s recommended you start with On Prices & Power, or perhaps with Equipment if you’re feeling like examining item listings.