There are many ways earning a altcoin, it depends on your own decision. Almost people participate on a bounty because they can get the coin for free and just follow their rules you can receive the reward. If you have any knowledge in that three you can participate in that all.
you can not get coins for free, you should put some work and time in it, maybe that is not much time, but reward is usually connected to time invested, and for sure, it is not for free