Well there's still a lot of ways to earn rewards without placing any investment, however, you should make sure that you have talent or skills that will help you to earn in crypto world. If have any talent in making such art, you could probably sell them for Bitcoin and just like what have others recommend, if you have any talent in making any multimedia art such logos then that would be great.
Having knowledge and skills in programming or maintaining websites would really put you in advantages because I believe that this is one the most high paying job specially in this kind of environment.