protonmail operates on a fremium service, you don't have to pay. I highly recommend the paid options though... and if you happen to have a webdomain, they'll manage an email server for you (which is a pain in the ass... and totally worth it. They do a good job.)
I mentioned in my comment that the prices were based off the cheapest "premium" plan. If I were to include freemium, tutanota, mailbox.org and others would also be free.