How much would it cost to build the Death Star?

You already know how much energy the Death Star would require to destroy Earth. You've seen the blueprints. But how much would it cost to build the Death Star, in real life?

The economics geeks over at Centives did some calculations, and based on just the cost of the steel required to build a structure of that size, they figure it would cost $852,000,000,000,000,000. "Or roughly 13,000 times the world's GDP. But then again, you can just take out a loan from the entire planet and then default on them in the most awesome way possible."

Of course, this raises some questions — like, is the Death Star really made of steel? Or some other alloy from that far-away galaxy? Also, wouldn't people with the ability to build something like that also have super-advanced methods for mining and processing metal, especially if they don't mind destroying a planet or two along the way? Finally, wouldn't the expensive part of the Death Star be that famous reactor core? [Centives]