Amber's economy, overall, is a classic maritime trading economy. Amber's own land mass is fairly limited, and most of its arable land is devoted to either subsistence agriculture or cash crops. It is heavily reliant upon Golden Circle kingdoms for staple goods, including food. While shadow-walkers can bring things in on an emergency basis, such imports cannot be done in the sorts of quantities needed to sustain Amber on a day to day basis. Amber's own craftsmen are highly skilled, and Amber produces a quantity of high-quality hand-made goods for local use and for export, but it also freely imports goods from other shadows, both in the Golden Circle and beyond. Moreover, nothing comes from nothing — what limited conjuration magics there are require sufficient effort and expense to obtain raw material that they are not in widespread use. Consequently, there is normal trade — usually.
Beyond the staple goods that people need on a day to day basis, Amber's economy is driven by novelty. Given the long lives of its people, entertainments and diversions and luxury goods tend to come as fads. The discovery or creation of something new and unique is a good way to get rich quick — while the fad lasts.
The nature of Amber, its reflections in shadow, and shadow itself, tend to complicate things, though. Fads in Amber tend to reflect into the shadows. The changing nature of shadow can cause unexpected surpluses and shortages, even the outright disappearance of certain things.
The appearance of the Black Road has been increasingly disruptive. The shadowpaths are no longer safe to travel, and dark things come out of shadow into Amber's borderlands, especially Arden. It has warped the nature of the shadows around Amber, and beyond, and its darkness has made itself manifest in a broad variety of ways — direct incursions, as well as pestilence, crop failure, strange warpings, and more.
What the noble Houses and the Golden Circle shadows trade in, and with whom, are up to their propcos. Mechanically, if a prop is particularly notable in a certain trade good, that prop is tagged with that keyword. Otherwise, it is simply color. Similarly, importance on a broad level is indicated by the prop's resource level, but the stated importance of particular trade (whether import or export) is color. You are free to make whatever background arrangements you would like to.
Props that do not have player propcos are considered to have negligible trade effects on play.
For various reasons (explained in the Lores), but notably because of the nature of infinite shadow, "realistic trade balances" do not apply to trade in Amber and its environs.
The shadowpaths, which can be sailed by any captain who knows the route and attendant rituals, connect Amber and the Golden Circle shadows. They are laid out in a hub-and-spoke model, where Amber is the hub. There are no direct shadowpath connections between Golden Circle shadows.
An Amber Navy picket guards the Amber-side entrance of each shadowpath, so that any ship entering a shadowpath from Amber, or exiting a shadowpath into Amber, is likely to be spotted, inspected, and taxed. If a ship does not receive an inspection at that point for some reason, it will be inspected and taxed when it docks at Amber or tries to enter another shadowpath.
As a result, Amber derives significant revenues by taxing trade, since those trading through shadow must pass through Amber.
Those who can shadow-travel independent of a shadowpath can circumvent the picket lines, but since the Navy has patrols in Amber's waters, it takes a skilled smuggler to completely evade the taxes (particularly if they plan to dock at any of Amber's harbors).