A Star Destroyer will cost $636 billion to build the parts on Earth, plus $44.4 trillion to get it all off Earth and to Mars. At that launch cost, it's definitely worth investing in asteroid mining and refining technologies first.

How much would a Star Destroyer cost in Star Wars?

Since those aircraft carriers cost around 10.44 billion each, a Star Destroyer would cost an estimated $464 billion. And that's the cost for Star Destroyers that can't really do anything: no turbolasers, no engines, not even any electricity. It's those extra costs that bump the total cost up to $636 billion.

How much would it cost to build a Venator Class Star Destroyer?

The Venator-class Star Destroyer cost 59,000,000 credits and was manufactured by Kuat Drive Yards for the naval operations of the Galactic Republic in the Clone Wars.