The economy of the interstellar age is very different from what it was before the Low Age. The abundance of natural resources in space means that bulk trading of interstellar commodities makes little sense. The prevalence of 3D printing and organic assembly means that the real market is one of open-source manufacturing data. With light lag preventing the fast exchange of economic data, the only real competitive markets exist with rare, unique commodities tied to a specific planet or culture.

1 - Resource trading, or the age of availability

The Low Age was a time of resource scarcity and local economies after the wanton consumption and destruction of the industrial era. Spreading to the stars changed this paradigm in many ways, the first one being the availability of basic resources. Advances in manufacturing, space propulsion, 3D printing and organic synthesis mean that a settlement only really needs four things to thrive: nutrients, metals, water and energy.

Water is incredibly easy to come by - while liquid water is rare, water ice is one of the most common resources in the galaxy, to the point some spaceships, like the famous spacecoach, are practically made of the thing. Water ice can be very easily collected and traded inside a system, with no need for interstellar trade.

Energy isn't exactly hard to find either, though its availability is more variable. There is no real unique source of energy in human space, though most systems operate on a mix of nuclear fusion, organic production and solar panels/wind turbines. Fusion only requires hydrogen from water or gas giant atmospheres, and renewable sources rely on positioning (gas giants are particularly prized as energy generation sites) rather than tradeable commodities.

Metals are a bit trickier to harvest but not much more than water ice. The vast majority of hard metals and rare earth minerals required by modern engineering can be found in rocky asteroids or spent comets, with little need for planetary mining sites. Now, metal abundance isn't the norm for all systems: for instance, systems with low metallicity stars like red dwarfs tend to have issues with metal availability, however, these systems are also very rarely settled, being cold, low-energy, hostile places. There are a few exceptions to this rule, however, such as the Trappist worlds, which are unusually rich in metals for red dwarf planets. Aside from isolated stations, there is little real need for interstellar metal and rare earths trade.

Soil nutrients are probably the most complex part of resource harvesting. Compounds such as nitrogen, ammonium or potassium can be found on asteroids, planetoids or in planetary atmospheres. Though they are not rare compared to human needs, they require more expertise and techniques than metal harvesting. Again, outside of isolated stations, the interstellar trade of nutrients makes little sense.

In the end, as far as basic resources are concerned, interstellar trade is nonexistent, with mostly inter-system trade between communes and cooperatives. Economies are local in scope.

2 - Manufactured commodities: the open-source age

The vast majority of complex manufacturing - except on Earth - occurs in space in order to cut the costs of surface to orbit transport and facilitate access to asteroid mined resources, which means it occurs under the umbrella of space-based communes, and they are entirely based around open-source data.

As far as interstellar trade is concerned the rules that apply to resource harvesting also apply to manufacturing: there is little sense in bulk trading at the interstellar scale when almost any commune can set up a 3D printing factory fed with locally exploited resources. The heart of this economy is data - blueprints, more specifically.

And within human space, blueprints mean open-source data. This is the most fundamental economic notion in the space age: what truly matters is data and there is no such thing as privately owned data. While there are secret or hidden blueprints, the immense majority of manufacturing blueprints, from spaceship parts to GMOs or spoons, are open-source data that can be freely shared, reused and built upon. This is an economy based on user collaboration, where designs and concepts evolve with time as new case uses and improvements are designed and there is no financial barrier to data access, an economy made possible by the post-capitalistic system of the communes. With light lag and interstellar communications delay, this open-source system exists in bubbles, so to speak, with each system having its collaborative forums and where innovations expand in "waves" between stars as courier ships travel through the void.