Several websites offer money (after a minimum level of earning) by clicking on advertisements. Hence, they are called paid-to-click (PTC) sites. One has to get registered before the project begins. Not all of these sites could be genuine, so be careful. One may also refer friends and earn money in the process. Some such sites are ClixSense.com , BuxP and NeoBux are some of such PTC sites.
Since time is the most precious commodity on this earth, invest the time at the front-end so that you can reap the benefits on the back-end. This means putting in a bit of sweat equity and not getting paid today. Rather, you'll get paid somewhere down the road. And you'll continue getting paid whether you keep building that passive income stream or you stop. It's obvious that this is the preferred route, but clearly the road less traveled.