Early editions of Google Apps for Business (aka G Suite aka Google Workspace) included a free version which included support for custom domains and catch-all email. Those accounts got grandfathered (i.e. stayed free) when Google discontinued them. The cheapest plan seems to be $72/year per user.

https://workspace.google.com/pricing.html

GMail has ads. It's free because you are the product, not the customer. Google's customers are the advertisers. The money has to come from somewhere.

I'm not talking about gmail. This post is about hosting an email with your own domain.

Google workspace isn't free.

Can't find any free plan either now. I guess they just discontinued them and are not upgrading existing accounts.

It's not been free for around a decade now. The free version was mostly a ploy to attract people away from Outlook at the time.