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.
How much will you make? I think my best month with Google AdSense was almost $5,000 over the last ten years. That amazing month blew my mind since it was actually near the beginning of my blogging journey. When you go from making zero to $5,000 in a month, that will rock your world. For me, it also got me even more excited because I knew there were other ways to monetize.