Going from either absolutely free to $50 /yr (for a very modest increase in features) IS a large leap. I would be happy to pay $10 /yr as a combined price/donation for the version that's now free if it included a couple more aliases (that are infinitely disposable). I would only upgrade to the $50 if it had many more features, including some of those voted on here plus some of the steathy options offered for pay in other email services (like throw-away and time-limited email address).

@Petr thats something that depends from your salary. I know that protonmail needs support. I would support it but 4 or 5 euros per month is a considerable amount of money.

I don't think it's expensive. ProtonMail is not a Google or Apple, and it doesn't earn millions of euros per month, it is a start-up that needs first several years a great support of it's users and fan community. I don't see a problem in using a free account, it's not that limited as you could think, because we all got used to Yahoo, Gmail etc. ProtonMail has the bright future. And we need to invest in this future, like we invest in new technologies buying new products released every year.

I disagree with this. Email is too important for your security and privacy online not to pay for. For anyone in a developed country current pricing is very reasonable, in relation anything else you're already paying for, such as Internet access and a computer. There's always the free service for those testing the service or financially constrained.

I would like to support Protonmail development with premium subscription. Current plans are however too expensive for basic users.
I would only need basic functionality, with possibility to create email aliases.

Or the other way around, give users possibility to opt out some current features from premium subscription with lesser money.