There are lots of ways available to earn money online without investment but you need skills to earn because bitcoin is also a money,no one will offer bitcoins for free.I think bitcointalk offers you a good rewards by joining signature campaigns for that you need to be a great poster with enough knowledge about crypto related informations.If you use bitcointalk forum only for the sake of earning purpose then you will be out of the game soon by the DT members.
Faucets is a way to earn bitcoins but I think it is not worth to do,it will just consume our time and you won't get enough rewards for our hard works through faucets.