There's no earning without investing. If you are talking about not investing money then that would be joining signature campaigns, faucets or offering services. But it also needs investment to start earning. Like investing your time, effort, knowledge, patience and skills. Every earning always needs hardwork.
Ideally, though, people could more readily find work payable in bitcoin. These days, it is still fairly limited (although I hear that Bitwage is growing). Since I don't have much money to invest at this point, I'm just doing whatever work I can that pays in bitcoin--signature campaigns, small tasks, etc.
