The founders aim to keep it free forever, should they want to earn money they'll add some non critical features so people who want to pay will keep the app running
>Q: How are you going to make money out of this? > We believe in fast and secure messaging that is also 100% free.
> Pavel Durov, who shares our vision, supplied Telegram with a generous donation through his Digital Fortress fund, so we have quite enough money for the time being. If Telegram runs out, we'll invite our users to donate and add non-essential paid options to break even. But making profits will never be a goal for Telegram.
[1]: https://telegram.org/faq#q-how-are-you-going-to-make-money-o...