The Germans had to pay a lot of money to make a submarine. Usually, Germany would have to send the order to a specialized work place, with specialized craftsman, and specialized parts made. I do not have the exact pricing of all of this, but you can imagine how expensive it must have been to have all of this done. They Germans would also have to pay the sailors and captains who worked the ships, pay to test the ships and their weapons. It cost a great deal of money just to produce one submarine by itself.