Batman is obviously just a normal (albeit very well trained) man beneath the cape and cowl, so why haven't any real-life billionaires ever suited up and started fighting crime? Perhaps it just wasn't worth the hassle. Or maybe the money. After all, the popular book Batman Unauthorised conducted a study into just how much it would cost to become the Dark Knight, and it's around the $300 million mark. Other estimates have placed it closer to $1 billion, but however you look at it, being Batman ain't cheap. For example, it would cost around $3.5 million to even put together a basic version of the Batcave, and the Batmobile is roughly the same price.