If you want free options, I often use MailEnable and hMailServer in lab environments. Also a free Azure developer trial includes some M365 licenses, and it pretty much always auto-renews every 90 days (I've had a few tenants going for YEARS now)
If you want free options, I often use MailEnable and hMailServer in lab environments. Also a free Azure developer trial includes some M365 licenses, and it pretty much always auto-renews every 90 days (I've had a few tenants going for YEARS now)