Tax consequences of liquidating a corporation
Using a long series of estimations whose details can be found in Rick's article he concludes that the annual operating cost for an airliner is about million (not counting fuel, landing fees, and taxes).
Written with help from a real live economist, this allows one to model interplanetary and interstellar trade with equations and everything.
The leader of the thalassocrats is of course called the thalassiarch.
This section is basically a rough outline of Rick Robinson's Interstellar Trade: A Primer.
Therefore it costs 0,000 per ton of cargo capacity per year to run a cargo starship.
This ignores taxes, station docking fees, and fuel.