The Douche Burger
666 Burger, New York
Cost: $666
Intended as a f-you to the rest of the expensive burgers with "rich people stuff" on them, The Douche Burger's quite possibly the most expensive food truck item in existence: a lobster-, truffle-, and caviar- topped, foie gras-stuffed Kobe puck that's slathered in champagne steam-melted Gruyere and doused with Kopi Luwak coffee bean BBQ sauce, then served in a gold leaf wrapper. The guy who sells it wears mink coats. Seriously, he does that.
As far as regular burgers go, if you're driving to Vegas from Arizona, the last stop is a burger restaurant called "last stop" hands down best normal burger I've had in my life.