I came across this article recently. Reliance Jio has been shaking up the mobile market in India with cheap prices. Turns out they also monetise by serving ads on the subscribers phones. From the article
fullscreen overlay ads. The ads appear intermittently but they’ll almost always show up after you disconnect a phone call or when you are charging the device.
It’s interesting that you can’t block some ads and they can only be disabled by customer care on request.
I wonder if this would work in our market? Would you mind having a few ads in exchange for cheaper prices?