we use mxroute, 21$/year for unlimited emails, domains, etc. 7200 emails per day limit (300 per hour) and it serves us just fine

they dont have that plan anymore, was black friday 2020 i think. but they have a 40$/year one thats similar.

would absolutely recommend these guys in production

or, you can set up your own mail server on a cheap VPS and use mail.baby to forward it so you make sure your mail gets delivered

lowendtalk.com/discussion/187043/mxroute-summer-2023-sizzling-deal-only-40-year