Subaddressing or + email alias workarounds for Office 365

Question

I have been searching for a free or cheap (about $1/user/month) workaround for days without success. All the workarounds that I came across were just for receiving but not sending (through the alias). The solution of using a 3rd party spam filtering service which also supports subaddressing may work, but the cost doesn't justify not switching to another email hoster like GSuite since I am paying for Office 365 anyway (unless there is a very cheap or free one that I could not find).

Regards.