According to a survey of 617 successful hackers by HackerOne, half of them earn more than $35,000 a year on bug bounties. Nearly 11% are making over $50,000, and 6% are making more than $100,000 per year.
And while most of them say that they hack for the money, and for fun, over 50% said that they also find these bugs just to help the world fight the bad guys.