Do note that the free plan is web only these days (no pop/imap) which is a showstopper for many.
We also use zoho but at this moment zoho.com domain is currently blocked https://twitter.com/zoho/status/1044249648993525760 so reliability can be an issue...
FREE PLAN - Up to five users. 5GB/User, 25MB attachment limit.
This is to have all 5 users in one "organization".
ZOHO offers full G-suite replacement, free. They have many more applications too.
I used the free plan for a few years, then started paying $24 per year for more storage. What you get for $24 per year is amazing. What you get with the free plan is amazing. Their business model is to impress you with their products enough for you move to a paying plan. They do NOT make money harvesting your personal information and selling it third-parties.