So basically, maybe for every 10 Serco ships destroyed the price of goods in Serco space goes up 5%, and same for Itani. That way, destroying enemy ships could actually have an impact on the verse. At the same time, to drive the price of goods down, selling stuff to Serco stations would decrease the price of that product, and of all ships/guns. Maybe for every 100cu sold in Serco space, the price goes down 5%?

Not a horrid idea but the numbers need serious tweaking.

The price of trade goods is already dynamic based on player activity. A more reasonable way to implement this would be for the purchase of ships and weapons to affect/be affected by trade goods. When you buy a ship, some group of goods that went into it's making might get more expensive, as would any weapons made with those goods. No magic price adjustments based on deaths, though; that wouldn't make a lot of sense in the context of the current economy.

For example, perhaps 1% of the price of a ship would be determined by the price of the "Hull Plating" good, and 1% by the price of the "Instrumentation Panel" trade good and so on. Similarly, maybe buying a Valkyrie could affect the price of Hull Plating as much as buying 8cu of it.

Yeah, that's what i meant - the more goods you have, the cheaper ships and weapons are.