This is the model for internet/Facebook access in several sub-saharan African countries and others:
https://en.wikipedia.org/wiki/Free_Basics#Participants
They've partnered up with large telecom operators in these regions to offer zero-rated Facebook access.
The Guardian has a couple of decent writeups about it too:
Facebook has been actively targeting developing countries that lack Internet infrastructure. They offer a walled garden consisting of Facebook and a few other sites for free. They initially called it Internet.org, but it’s since been renamed Free Basics.
I guess the concern is that people will confuse Facebook for the Internet, and they’ll think they’re getting the Internet for free. It then becomes very difficult for a real ISP offering full Internet access to enter the market.
The Guardian has a couple of decent writeups about it too:
https://www.theguardian.com/world/2016/aug/01/facebook-free-...
https://www.theguardian.com/technology/2017/jul/27/facebook-...