Though Open Mbox does provide free email service, we also have the paid plans which some users might have interests in.

Function Mailplus Free
Disk Quota 5GB 350MB
Outgoing Mails per Day 150 9
IMAP/SMTP yes yes
Advanced Webmail yes no
Custom Filters yes no
Domain Email like Fastmail possible no
Premium Support yes no
Daily Backup yes yes
Cost $19/y $0