Mail-in-a-Box lets you become your own mail service provider in a few easy steps, and it is open source, so the software is free. Its sort of like making your own gmail, but one you control from top to bottom. In addition, you get Nextcloud, so you have a place for files, calendar, and contacts. Technically, Mail-in-a-Box turns a fresh cloud computer into a working cloud storage and email server. But you dont need to be a technology expert to set it up, just follow the install instructions carefully.