Australian Comedian Dave O'Neil wanted to upgrade his seat on a flight from Melbourne to Perth to one with a little extra legroom and wound up being charged $987,999,999! (That's about $770 million USD)
Obviously (hopefully) Dave assumed this was just a glitch in the app but still, his handling of the situation was far more polite than anything I would have managed. He tweeted the company that he was "very happy" to pay for the extra legroom but the amount seemed "a bit expensive."
The company did investigate the issue and confirmed that, despite what the app said, he was only charged the correct $70 AUD fee. In the meantime, nothing was about to stop Twitter from having it's fun...