In a humorous variation, Batman has also used his fortune to simply bribe the villains to stop whatever it is they're doing. Arguably the best moment came in an episode of Justice League, when the Ultra-Humanite agreed to betray the rest of the villains after Batman offered to pay double what Lex Luthor was paying him, which he uses to make a huge donation to American public broadcasting. Unlike the rest of the villains, who were all shown to be in a bad mood in jail at the end of the episode (especially Luthor, who is really pissed in the cell next to him), the Ultra-Humanite was happy and content as classical music was piped into his cell.
In an issue of Justice League he managed to get mercenary villain-team-member Mirror Master over to his side simply by offering him a raise over what Lex Luthor was paying (along with a sizeable donation to the orphanage where Mirror Master grew up).
Bruce is also a subversion as it is shown numerous times that he also uses his cash to give to charity a lot, and when he's not crimefighting, training, or bonding with other crimefighters, he's doing charity work through his Wayne Foundation, which has Lucius Fox handling the details about a charity that addresses social problems encouraging crime as well as helping the victims. It is amazing to note that he built up a reputation for being somewhat of a reclusive lazy playboy despite the fact that he is arguably the worst workaholic on the planet. Then again, this is wholly intentional on Bruce's part.
This trope has also been deconstructed with Batman in stories where he has lost his wealth or access to it. The loss does impact him and limit his effectiveness though he is resourceful enough to make do with just his wits and skills. Though without his wealth, he would never have been able to acquire said knowledge and skills in the first place.
The 2017 film Justice League, has him quite bluntly noting this to a curious Barry Allen:
Barry: ...what are your superpowers, again? Bruce: I'm rich.
In Zack Snyder's Justice League, Bruce brings $25,000 in cash with him to a remote village in Iceland just for information about Aquaman's whereabouts in order to recruit him into the Justice League.
Bruce isn't alone with this. His kids have taken after him. At one point in Nightwing, Dick convinced Deathstroke to drop an assassination contract by paying his fee plus a dollar. Deathstroke dropped it just because of Nightwing's balls.
Dick Grayson has enough money to finance his crimefighting career, buy out the circus he used to perform in, save it from financial ruin, and tweak the formula enough to turn it into a success. He also takes on various real-world jobs from time-to time (Such as being a cop), not because he has to, but because he has enough money that it doesn't matter what he does during the day and so he does whatever the hell he feels like.
Of course, this comes to a head during the New 52, where thanks to the devastation of Death of the Family and The Joker, Nightwing spends a good part of his stay in Chicago (relatively) dirt poor—and thanks to the demolition of the Bat Family's trust of each other and personal pride, he pointedly refused to ask Bruce for financial help.
As of Infinite Frontier, Nightwing discovered that he was the sole heir to the estate of the recently deceased Alfred Pennyworth who, thanks to some shrewd investments, left him with billions. He is now devoting the bulk of his newfound fortune to rebuilding Bludhaven by establishing the Alfred Pennyworth Foundation.
In Robin: Son of Batman, Damian pays Deathstroke off so that he'll leave his new teammate, Maya, alone.
If Robin is to be believed, just the "Batarang budget" is large enough that he can hide the costs of secretly shipping a Batmobile across the country within it. And probably pay for the car itself as well.
Green Arrow often fits into this too. His fortune is mostly limited to developing new Trick Arrows. And even then, he's regularly just using the normal pointy kind.
His origin story revolves around being rich enough to have fallen off a yacht (though apparently, not rich enough to have anyone come looking for him for months).
Another advantage to wealth: In one story from the forties, a bankrupt Green Arrow had to find a job and restrict his crime-fighting to lunch breaks.
To make the character fit the mold of a social crusader he wanted in the 1970s, Denny O'Neil wrote a story where the person charged with running Oliver Queen's corporation embezzled the money from it, leaving Arrow penniless. He spent most of the rest of his tenure middle class or worse until he was killed in the mid 90s. There's no evidence he left anything to his son Connor, though he had enough to have The Shade cover his tracks after his death.
After being resurrected, Green Arrow was left a house and a tidy sum of money at the end of the "Quiver" storyline by Kevin Smith.
Prior to Flashpoint, it appears that Arrow's civilian identity (Oliver Queen) is a well-respected philanthropist. He had enough money to run for mayor of his city, and financial resources to rebuild his home/headquarters after it was blown up around the time of Infinite Crisis. Before Cry for Justice at least Oliver Queen was established to have taken the "millions" of dollars he got from Stanley Dover's will and through investment, especially his market manipulations, to have become significantly wealthier, hundreds of millions to low billions range is probably what we should assume Ollie has access to.
The New 52 version of Green Arrow was running an Apple-like subsidiary of Queen Industries (Q-Core) and had a number of trick arrows and a high-tech base. Green Arrow (Rebirth) runs a version of the embezzlement storyline to get him hiding in the woods without a penny to his name and a murder charge hanging over him.
Most Excellent Superbat, leader of the Super Young Team (who first appeared in Grant Morrison's Final Crisis), takes this trope quite literally, as seen in the picture above. To quote Superbat himself, "Let me show you what money unleashed can do!". In the conclusion of his team's mini (Final Crisis Aftermath: Dance), he repaired the damage Final Crisis did to Japan by BUYING the country! And of course the Super Young Team as a whole gets by mainly on his extremely ridiculous wealth.
The second Blue Beetle, Ted Kord, was occasionally rich enough to fall into this trope.
Princess Projectra was this in the "threeboot" of the Legion of Super-Heroes until her planet blew up and she got her parents' illusion powers.
Steve Dayton, aka Mento, of the Doom Patrol. He bought his superpowers.
Nite Owl II from Watchmen is a deconstruction of this trope, at one point openly admitting how spending millions on dollars on crimebusting equipment to fight purse-snatchers and prostitutes isn't exactly the most economically sound thing to do. Which is why Ozymandias decides to take it to the next level by actually deciding to save the world with all the money he has. Sort of.
The short-lived New 52 series The Green Team was all about this trope. It starred teenage trillionaires who purchase gadgets and superpowers, although most of the crimefighting was reluctant on their part.
Deconstructed in Marshal Law: the Private Eye (a Batman expy) battles crime with his genetic enhancements and family fortune funded equipment. But the real reason he's fighting crime is to lash out at his parents using him as a guinea pig and make sure that no one can take away his wealth after he had his parents murdered. And his crime-fighting methods are so brutal, that violent crime has actually gone up significantly
