ckickfight.
This is the best game in the world.
By the way, he pays in bitcoins even without investments.
I would post a link, but it's probably not allowed here

In this game, you need to shoot bots from which rewards fall out.
If it's boring, then you can fight with other players. You can be a loner, you can join some kind of gang, or create your own gang and fight with others.
This is a very exciting game.