When the private sector creates ships, it pays a fee to the state through spaceport fee. Is this fee the price of the ship?
When the private sector orders ships, the state gets paid the purchase cost of the ship. This is also true for mining and gas mining stations.
When the state buys ships, it has to pay...to the private sector?
Would buying ships then imply to transfer money to the private sector?
I don't know what happens to the money that the state pays when it orders up a new ship. I suspect that the money just disappears, but as I have never actually paid attention to the private sector's funds when I buy warships I cannot say with any certainty that this is the case.
Is there any exchange of money in the process? If so, who is paying?
As I understand things, the private sector of the empire with which the freighter is registered pays the value of the resources to the private sector of the empire which controls the location from which the resources are being collected whenever a freighter collects resources from a location (at any rate, it works this way at state-owned stations; I'm not sure about private sector mining stations, for two reasons - one, I haven't paid that much attention to it, and two, the transaction values are usually rather low*). If there is a commerce center at the location where this occurs, the private sector of the empire controlling the location pays a percentage of the transaction value into the controlling empire's treasury. Free Trade Agreements, Mutual Defense Pacts, and a character skill are supposed to increase the value of foreign trades, increasing the revenues generated for the state by this activity, though I'm uncertain if this also comes out of the private sector's pockets or if the bonus just appears.
*The percentage that the state takes is the percentage listed on the commerce center component, which if I recall correctly ranges from 4% to 15% depending on component upgrades. It is somewhat unusual for a single freighter to pick up more than about a thousand units of resources at any one time, or at least so it would seem from the handful of spot checks I've done in the past. Resource costs for most resources range from ~0.83 to ~3.3 credits per unit, if I recall correctly, and will likely be on the lower end of that scale if you've built up a healthy number of mines. This means that the state's take from any one transaction is likely to get lost in the noise unless you're paying quite a bit of attention, and may still be lost even then because the cash on hand displayed in the top right corner of the main window and in the empire economy overview is rounded and not always instantly updated.
I have the feeling the state never has to pay for said ressources, except for fuels (caslon and hydrogen).
The purchase and maintenance costs of a ship are supposed to be determined by a formula involving the total value of all the resources required for ship construction. When the state orders a new ship, the purchase cost in essence represents the state buying the resources to build the vessel, along with paying for the labor and space in the dockyards; the maintenance costs are essentially an abstraction representing ongoing costs of purchasing replacement parts based on the costs of the resources required to build the ship, though within the actual game resources are not consumed for either upkeep or repairs on ships in service. There's an old post about it, if you're curious (note that the second reply to the thread linked has corrections to the formulae listed in the first post). If I recall correctly, the formulas appeared to be correct the one time I checked, but it's been a while; at the least, the formulas should be reasonably close to accurate for the current version of the game.
Note that the resource costs listed in the Expansion Planner are rounded more than the values which the game uses to compute the purchase and maintenance costs are, so even if the formulas in the thread linked are perfectly accurate you will probably see some error between the purchase and maintenance costs you compute using the formulas and the values you see within the game.
Do the ressources belong to the state then? Or is it still in the hands of the private sector?
I would be inclined to say that the private sector owns the resources. Note, however, that "the private sector owns the resources" is not the same as "the private sector can use the resources without paying for them" - private sector ships and stations have to pay for fuel and follow the same construction and maintenance cost formulae as the public sector ships and stations.
Finally, how could I use the economic system at my advantage. Is there any way to leverage an advantage out of it?
If you're looking to trade, checking out the galaxy demand for resources in the Expansion Planner and focusing your mine-construction efforts on resources in high demand over the galaxy isn't a bad idea. You may also be able to use the Galaxy Map's resource filter to get an idea of which areas have what resources and try to get Free Trade Agreements with empires in regions which lack resources which are abundant in the region in which your empire is found. Be aware that long-distance trade can take freighters out of circulation for a very long time; even fully-upgraded Torrent Drives take 55 seconds of real time at normal game speed to cross just one sector, not including jump initiation time and docking/departure maneuvers. Also be aware that it's fairly likely that a freighter will make at least a part of any given trip empty, as the computer tends to issue orders to idle freighters before it queues up orders on active freighters.
I wouldn't really recommend worrying about anything much other than that, as far as background trade is concerned. You don't really have any good tools for manipulating it (and there are some reports suggesting that some of the tools you have for manipulating it - namely, blockades and trade sanctions - don't work). You may want to consider looking at the Component Guide in the Ship Design menu to better match the resource requirements of the ships you design to the resources available within your empire, you should probably try to have at least one source of each strategic resource "close" to each of your major shipyards, and you probably want enough mines overall to keep resource prices down, but that's about it.
< Message edited by Aeson -- 3/13/2017 3:56:08 AM >