I'm Asking

Can I Make Money By Free Game????

I think that the question is kind of vague.

Well, you can try put some ads... you can ask for donations, open a patreon, who knows.

What were your thoughts on this matter exactly? 

If you're asking whether people will donate money for a pay-what-you-want game, the answer is yes.

In one of my games, I offer exclusive files that can only be achieved through donating.

Well, if you have a Patreon and people supporting you, then yes, you could make money by making free games.