Hi NZK,
it is not yet revealed how trading will be realized exactly. The current implementation is very rudimentary, the development was focused on combat until now.
But it's safe to say that you will be able to operate big trade fleets. You will probably ferry a multitude of goods through the sector, open your own outpost for trade or mining and have to protect all that from envious competitors or pirates.
The economy dynamics will likely be based on supply and demand, and will be tightly woven with the overall civilization status of a solar system (you might be able to bring a system to its knees with embargos, blockades etc. or safe it by breaking those).