Thirty-two years ago, I did a semester of macroeconomics at Gothenburg university. Many of the lectures dealt with scarcity and pricing mechanisms. I was more into political science and economic history, so I did not pursue that discipline.
But the knowledge I had gained helped me in designing mechanisms for for “international trade” in gameworlds, no matter whether they were in space or on planet surfaces. I tended to emphasize the exchange of technological products for raw materials (e.g. cellphones for oil) and the importance of rare metals in hitech industries (e.g. superconducting alloys contain a lot of unusual metals). One particular interstellar trade specialty is expertise, i.e. well-paid consulting experts going to far-off places to assist in industrial endeavors.
Here is an interesting glance at the macro-economics of some sensible, or less sensible, space empires — link >>> (Dune may be a well-designed world, but, no, I don’t buy the politico-economic structure of the Padishah Empire.)