I may be wrong but I can't think of any markets that will charge a tariff on exports. They should encourage exports because it brings money in from the outside.
Try thinking of it as a sales tax. Maybe modern governments don't impose export fees (I don't know, though I'd rather doubt that there isn't at least some fee applied), but I'd be willing to bet that any transaction that transfers ownership of the item from the manufacturer to the shipper gets hit with some form of sales tax. 30% is a very high sales tax, but not an unheard of sales tax.
But that doesn't address the basic problem with trade pricing. Either we as players aren't getting enough info, or there isn't reasonably profitable trade routes without taking advantage or shortages. I should be able to loadup 200 units of food from a place that produces it and unload it as say a orbital station for a reasonable profit. So far I haven't been able to do that. Part of it is the tariff system, but overall it just seems off.
When buying for 130% of the list price and keeping 70% of the sales price, you need to sell for at least ~1.86 times the purchase cost to break even on the cost of purchasing the goods. Factoring in the shipping costs raises that a bit, so it's probably only worth intentionally carrying cargo from point A to point B when the price at point B is at least double the price at point A if you're running your shipping 'business' based on current demand.
The big reason is the extreme 60% tariff. And don't even get me started on the expensive custom scans... I understand the need/want for the tariff, but 30% buying and 30% selling is insane.
The tariff isn't 60%; it's closer to 30% of the total value of the transaction. For example, if you sell food for 2 credits before tax and purchased it for 1 credit before tax, the tariff amounts to about 27.3% of the total value of the transaction, leaving you with a profit of 0.1 credit per unit of food traded; total taxes paid is 0.9 credits per unit of food traded out of a transaction value of 3.3 credits per unit of food traded (1.3 credit to purchase, 2 credits for the sale). The more extreme the difference between the purchase cost and the sale price of the good being traded, the closer the tariff comes to 30%; for example, food sold at 240 credits per unit and purchased at 30 credits per unit (not terribly uncommon when buying at Tartessus and selling at any world with a decent food shortage) results in 29% of the total value of the transaction being taken in tariffs. If you're evaluating the tariff relative to the sale price at the destination, you could come up with higher numbers, although it's difficult to evaluate that without knowing the purchase cost, though by this metric the effective tariff goes to 30% as the sale price increases relative to the purchase price; even by this metric, the tariff by this metric only reaches 60% if you're selling at the same price you purchased the goods at (if you're selling for less than you purchased the good for, the effective tariff can be larger than 60%), while the tariff is 45% of the sale price if you're selling at twice the purchase cost, and it falls further the greater the disparity between the sale price and the purchase cost becomes.
If you're evaluating the tariff relative to your profit, I don't really even want to go there, as the numbers are extremely variable; in the case where you sell for twice the nominal purchase costs, your tariff payments are 9 times greater than your gross profit before shipping expenses, while if you're looking at selling for 8 times the purchase costs the tariff is about equal to 63% of the gross profit before shipping expenses. (Note that the tariffs are not included in shipping expenses and are accounted for when computing gross profit; shipping expenses are fuel, supplies, and customs inspections, which cannot be evaluated without knowing where you came from, where you went, how you got there, and how lucky you were along the way.)
And irl, even the winner never makes money off of battles. The only ones who do are the ones who sell the weapons!
History would like to disagree with you. Some pirates were quite obviously able to turn a profit off of battles, otherwise piracy would have dried up without requiring the intervention of the navies of any nations, even if it's not necessarily commonly profitable (all that needs to happen is for there to be enough success for a few that people decide there's easy money to be had). The history of prize law strongly indicates that at the very least some of the higher ranking members of the crews of naval vessels involved in engagements where ships were captured stood to make significant amounts of money off the action. Given the values listed on Wikipedia's page on it, it wouldn't surprise me to learn that naval engagements that took a decent merchant vessel as a prize could work out to a net profit for the nation whose warships took the prize.
