Google Apps with a custom domain was once free for as many email accounts as you were approved for. There are a handful out there with lots more than 10 free accounts. They don’t get support, have less space provided, and can’t use the outlook connector so it’s not an equal comparison. It’s nice that google hasn’t changed this on their users.

Zoho recently restricted their free custom domain service for email. Not sure who is the best free option out there now.

I have my own domain name through Google apps and use a naive mail client to access gmail. As soon as the handful of people I talk to exclusively on hangouts migrate elsewhere, I'm ditching Google as a back-end. I'd never have predicted this in 2008. Back then Google still cared about UI speed.