Business Class Email/Exchange Online Plan 1, for an unlimited number of users, drops back to a very limited feature set. You get email management and shared calendars, plus Active Directory, but no Office suite licenses. Price is $48 per user per year.
Office 365 Enterprise E1, for an unlimited number of users, still doesn't include Office licenses. You get the features in the Business Class Email package, plus online conferencing, screen sharing, and instant messaging (which, as noted earlier, are available free from many sources). You get SkyDrive Pro, which offers 25GB per user, plus tools to control access to the data. And you get SharePoint with shared email and document folders, free website hosting, plus Yammer Enterprise. That's all of the glue, but none of the Office apps, for $96 per person per year.
Finally, the big kahuna, Office 365 Enterprise E3, offers all of the above E1 features plus an Office subscription for each user (one subscription covers up to five PCs or Macs). You also get the iPhone and Android Office Mobile apps, archiving and legal hold capabilities for email, a legal compliance tool called eDiscovery Center that puts all of your main Exchange, SharePoint, and Lync data in one place, voicemail, and the Power BI tools for data analysis. Office 365 Enterprise E3 runs $240 per person per year.
Still need licenses for the Office desktop programs? You can mix and match any of the above plans with subscriptions to Office 365 ProPlus or you can buy (er, rent) Office 365 ProPlus without any of the other plans. Each subscription can install up to five copies of Word, Excel, PowerPoint, Outlook, and Lync on PCs or Macs, plus client-only subscriptions (no server) for OneNote, Publisher, and Access. You also get Office Mobile for iPhone and Android. If you already have a Software Assurance license, you can move it over to a new Office 365 ProPlus subscription.
I won't even mention the Exchange Online plan, the SharePoint Online plan, Lync Online, or the Kiosk plan. I've also glossed over the Volume Licensing plans for Office 2013 and Office Professional Plus 2013, with or without Software Assurance.
There are also specialized versions of Office 365 Government, Office 365 Education (as of Dec. 1, 2013, schools with Office 365 ProPlus or Office 365 Professional Plus licensed for all of their staff and faculty can get free Office 365 ProPlus licenses for all of their students), Office 365 University (four years of Office 365 on two PCs or Macs for $80 — and you can renew the four-year subscription once, as long as you renew before you graduate), and Office 365 for Nonprofits (free to qualifying organizations).
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