There are good options that are far cheaper: * Mailbox.org has a per mailbox price that starts at EUR 1 per month * Runbox has similar options * Mailfence is

There are good options that are far cheaper: * Mailbox.org has a per mailbox price that starts at EUR 1 per month * Runbox has similar options * Mailfence is another one, but I have no idea how easy it is to use for setting up the custom domain and mailboxes (last I checked quite sometime ago, the setup involved contacting them) * Migadu has an "all you can eat" pricing that starts at USD 48 per year, with restrictions placed on how many emails you can send per day. For those who don't use email accounts to send a lot of mails, I don't think there's anything that can beat Migadu on price. All the above providers are based out of Europe. All of them provide direct IMAP support (unlike ProtonMail where you have to use a bridge application). For those who don't mind US based hosting, Mxroute is another provider that's slightly similar to Migadu on the hosting several mailboxes for a fixed price.