I want to ask how does the people that do bounty make money.I mean they are giving away money for free.How is it profitable for ICO teams?
Because very less amount of people invest in their ICO through bounty.

Of course, doing bounty campaign is profitable enough for some ICO teams, specially when a project having a very good platform and very useful product to someone. The reward they distribute after the ICO is just a small amount compared to their total token distribution, so it will really give a huge profit to the project if it will be successful.