I would be interested in this... but there are a lot of red flags. People have posted comments and reviews that are bad. And the demo does not even work at all. Shame this could have been big. I purchased startapps plugin before and that never worked either.
Viewing post in C3 Plugin META Audiance Network PRO comments
try the free version first, if it works you can buy the pro version
https://www.construct.net/en/make-games/addons/504/facebook-fan-ads-supports-c3