That leaves us with Two-Face. Former District Attorney and golden boy of Gotham, Harvey Dent, took a tragic turn towards villainy when Boss Maroni threw acid on his face, shattering him both physically and mentally. Since then, Two-Face has held Gotham at ransom numerous times (though never succeeding thanks to Batman), has hired plenty of henchmen, bought several weapons, hideouts, cars, clothes, etc., and staged elaborate schemes that inevitably involve large sums of money in order to capture Batman. This begs the question: Where does he get this money from?
One might argue that Two-Face has enough saved up from his time as District Attorney, that he hasn't needed an additional source of income. But consider this: surely the government would have seized whatever assets he owned once he escaped from Arkham for the billionth time. Further, his pay as DA of Gotham City was likely meager, considering that public prosecutors do not get paid that much. Take a look at this image, reprinted from Payscale.
Clearly, Harvey was a young gun: he had just been a DA for a few years before his accident. Conservatively, I will say that he served as DA for 1-4 years. That means his average annual salary was approximately $57,000 a year. And this is by 2008 standards. Recall that by modern continuity, his accident occurred in 1996. All of this means that Two-Face cannot possibly have enough money saved up to conduct his elaborate schemes against Gotham City and Batman.
Here's another theory: perhaps Two-Face has all his money from bank robberies or underground drug trafficking, criminal activity, etc. This could be true, but we happen to know that the Batman is pretty good at rooting all of these mechanisms out. And I do not think that Two-Face has pulled off enough successful robberies to sustain him throughout the years.
So what's left? We know he does not launder money through a business as the Penguin does. We can assume he does not have money saved up and that he has not scored big enough through crime to sustain his operations for over a decade. And now post-RIP, Two-Face is in a gang war against the Penguin, requiring even more resources to keep up.
The only theory I have is that perhaps he has a private investor; someone deep in the underworld of Gotham benefits politically or financially from Two-Face's successes. I used to think this person was the Penguin, but being that they are now at war with one another, this is unlikely.
Any thoughts from the readers?