Board Game Arena

One of them says you only pay a total of 2 instead of 7. The other one says you get a discount of 2. A discount of 2 from a cost of 2 results in a cost of 0. If you spent fewer cards, you would have had to spend money/fuel to pay the difference in the cost

You might have encountered a bug if you were required to build 3 ships to complete that goal. I've completed that goal with just a single ship before. If you get each different pair of colors, then you have 2 of each color icon within that ship, which will complete any level of that goal except for ...