Warning! Spoilers for Batman: Killing Time #3 ahead!
Fans speculate and even joke about what Batman carries in his utility belt, but after the Batmobile is destroyed, he confirms what his most valuable secret weapon is. It's not a shark repellent spray or Batarangs, but a weapon he owes to his Bruce Wayne identity.
The limited series Batman: Killing Time by Tom King and David Marquez depicts the early days of Batman's career, when many of his most dangerous villains team up for a daring heist. While Batman is distracted with Killer Croc, Catwoman and the Riddler work together in order to steal a mysterious object for a client. In doing so, the Riddler betrays Penguin, leaving him near death. To get his revenge, Penguin hires a hitman called the Help to track them down and make them pay.
Fortunately for the villains, Batman intervenes and stops the Help from finishing Riddler off in Batman: Killing Time #3. While Batman is distracted, Catwoman and the Riddler take off in the Batmobile, crashing it over a cliff in the process. When Batman finally catches up to the wreckage, he needs a way to pursue them. So he goes to a local bar and commandeers a motorcycle. Before taking off with it though, Batman leaves some money and a "Thank you" note for the motorcycle's owner. Specifically, he leaves $97,438, effectively buying the motorcycle from the man for well over market value.
What's fascinating about this interaction is that although it seems simple on the surface, there's nothing simple about it. Batman is in the middle of a chase. He doesn't have time to go back to the Batcave or Wayne Tower and grab the money, and he certainly doesn't go to an ATM to take it out. The only explanation is that Batman has all of that money on his person, most likely in his utility belt. It's kind of crazy to think that not only does Batman carries cash with him, but that he carries nearly $100,000 of it.
This strange yet interesting detail about Batman is strangely reminiscent of one of the most cringe-worthy moments in Batman film history. In Batman & Robin, Batman takes out a "Bat" credit card. It's pretty ridiculous, but in a strange way, a credit card is definitely more practical than Batman carrying a huge envelope of cash for whenever he might need it. It probably wasn’t Tom King’s intention to reveal this detail, but still, it’s the only logical explanation for how Batman got the money he needed to purchase the bike.