A Microsoft 365 alternative for email only
Business Basic is a bundle. If you use one part, you pay per person for the rest — here is the arithmetic and what breaks if you leave.
Microsoft 365 Business Basic runs about $6 per user per month on an annual commitment. That is a fair price for what it contains. The question worth asking is whether you are using what it contains, because the bill is per person either way.
What you are actually buying
Business Basic is Exchange Online for mail, plus Teams, plus SharePoint and OneDrive, plus the browser versions of Word, Excel and PowerPoint, plus an admin centre with compliance and retention tooling. Mail is one line item in a bundle that was priced as a whole.
This is different from the Google Workspace version of the same question in one important way: Microsoft's mail half is Exchange, and Exchange is genuinely hard to replace if you use it as Exchange — shared calendars with free/busy lookup, resource mailboxes for meeting rooms, delegate access where an assistant sends on someone's behalf. Ordinary IMAP does not do those things, and no amount of price advantage makes it do them.
The arithmetic
| Team size | Business Basic at $6 | Per-domain at $10 | Difference |
|---|---|---|---|
| 2 people | $12 / mo | $10 / mo | 1.2× |
| 5 people | $30 / mo | $10 / mo | 3× |
| 10 people | $60 / mo | $10 / mo | 6× |
| 25 people | $150 / mo | $10 / mo | 15× |
At two people the gap is not worth a migration. At ten it pays for something else entirely. The shape of that curve, rather than any single row, is the actual argument.
When leaving is the wrong call
- Anyone books meeting rooms or checks colleagues' calendars from Outlook.
- An assistant sends mail on someone else's behalf (delegate access).
- You are subject to retention or legal-hold requirements and use the compliance centre for them.
- Teams is where the company actually talks.
If two or more of those are true, replacing the mail provider does not save you $50 a month. It saves you $50 a month and hands you a project.
When it is the right call
The common case is a company that moved its chat to Slack, its documents to Notion or Google Docs, and its calls to Zoom — and kept paying Microsoft per person so that the domain has mail. At that point Exchange is doing exactly one job, and it is a job that costs the same whether you use one feature or forty.
What to check before you move
- Shared mailboxes. Exchange gives them away free of a licence. Make sure your replacement has an equivalent — a real mailbox or an alias — for every one you rely on.
- Distribution lists. These become aliases pointing at several people, or a mailbox everyone can open.
- Calendar. Export to
.icsbefore the tenant is gone; calendars are the thing people forget until they are missing. - Mail history. Export mailboxes to
.pstor pull them over IMAP while the account is still live.
Do the export first, the DNS change second, and keep the old tenant paid for a month after mail starts arriving in the new one. Mail is one of the few systems where rolling back after the fact is genuinely painful.