One of the most interesting aspects of Brunelleschi: Age of Architects for me is the open economy. The flow of resources, goods, equipment, and currency between the game system and the players and between the players and each other is very open ended - allowing a variety of economic systems to be implemented and played with. Having such an open ended system can be confusing, so I'm going to outline some of the major aspects of it here.
From here on I'll refer to game resources, goods, equipment, and currency under the umbrella term 'items'.
Items in Brunelleschi can be obtained through a variety of mechanisms:
While not all actions, buildings, and scenarios produce items, many of them do. Actions and scenarios will generate output for anyone utilizing them, while buildings grant their output only to their owner unless they are taxed.
Through the markets trades of any items for any other may be negotiated.
Additionally, friends and allies may choose to simply 'donate' items from their inventory which does not require the creation of a market order.
There are multiple types of taxation options in the game, which allow a Sovereign to dictate the flow of items in their settlement. Through the Manage->Government menu, a sovereign may choose to set a specific tax rate on the output of Harvesting buildings and a separate rate for Processing buildings; these route a percentage of the output from those buildings to the Sovereign even if they are overseen by a Minister or even privately owned.
A Sovereign may set these rates to 0% to allow Ministers and residents to keep and manage all of their building output, or may even set it to 100% to insure that all such output is routed to the Sovereign's stores.
In addition to building output, a Sovereign may choose to tax imports into and exports out of their settlement. When import or export taxes are set, the tax price is added to effected market orders and the taxed amount is automatically routed to the tax issuing Sovereign.
Action output may also be taxed by a Sovereign, meaning that a portion of the item rewards for every action taken within their settlement are routed to the Sovereign.
Ministers may also Harvesting and Processing tax rates which apply only to their District and which are determined after Sovereign taxation is taken into account.
All these various mechanisms for exchanging items allow each settlement to determine and regulate an economy suited to it specifically. On a personal note, I very much look forward to seeing the various types of setups people put together and administer in their own settlements, as well as what kind of economic setups non-Sovereigns will seek out to live in.