Usually, 2-4weeks after the ICO. But it is also depends on the manager of the bounty you wherein. Before joining in any bounties, make sure to read first all the rules and general terms to know all you need to know to be a good bounty member. You just need to wait your wages in the bounties after the ICO. Managers needs time to distribute all the tokens he hold and finished all the work he need to do to  make all the participants clear.