CAM4 and Chaturbate are free… meaning they don't try to ask money just to watch like instead Flirt4Free and similar. You can tip or just watch and there are limitation, but for example on Chaturbate you can watch more than 1 cam at the time without paying. The rest is left to the performer... there are some that show for free and "finish" other that even paying keep only teasing or jerking off but go away without cumming... no guarantees, but it's really free if you can find the right model.
Maybe if you are good (in shape, big cock, funny, this kind of things) you can also get tips or find someone for c2c free...