Therefore it costs 0,000 per ton of cargo capacity per year to run a cargo starship.
Therefore if the cargo was available for free at the origin the minimum selling price at destination is $100,000 per ton, or $100 per kilogram.
The implication is that only very high value cargo can be profitably shipped interstellar.
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 $30 million (not counting fuel, landing fees, and taxes).
An airliner's purchase price is $100 million so one year's uses costs about one-third of the purchase price.
A cargo jet can carry 50 tons so its purchase price is about $2 million per ton of cargo capacity.