Lots of projects don't pay bounties, just like lots of projects don't deliver what they promised on their ICO. Pick you bounty campaign carefully. If you are unable to do so, just give up, because working for free is really bad for your soul. And pockets.
first choosing a campaign is very easy, even definitely getting paid, but now choosing a campaign must have special expertise where the ICO market is very bad, and not many successful bounties.