In case you were thinking about building one, Rick Gold has calculated the approximate price of constructing your own Death Star:
While watching [Star Wars], an odd question popped into my head, “How much would it cost to build the damn thing?”. Impossible to figure out? Truthfully … yes. A complete and utter waste of time, absolutely! So why not try and find out!
... Add it up, and we have a figure of exactly $15,602,022,489,829,821,422,840,226 and 94 cents. Tell you what, I’ll pitch in the 94 cents.
In other words, only 1.15 trillion times the U.S. debt. And that doesn't include feeding the Stormtroopers.