I subscribe to Office 365 Personal since I’m a one man band. I chose the one year payment option so that costs me $69.99 per year. I also require Access so that I can develop SharePoint Access apps so that is another reason why I went with the Personal version.
As I mention on the blog’s About page, SharePoint is viable for small business because of the SharePoint Online version. I subscribe to Plan 2 because it comes with Excel Services, PowerPivot, and PowerView. You can do business intelligence reporting using these services and Excel. The Sales Pivot Chart post shows the use of Excel Services. This costs me $8/user/month. There is a $5/user/month plan (Plan 1) but I normally don’t recommend it since you will likely use Excel Services.
So I’m paying Microsoft $166 a year.
I recommend that most organizations subscribe to one of the Office 365 plans that bundle Office and SharePoint together. Office 365 Enterprise E1 provides cloud versions of Office, meaning they don’t run on a PC, for $8/user/month. Most users do not need a desktop version. Those that do can get a desktop version or the Office 365 Personal version. If you have a large number of users that require Office than Office 365 Enterprise E3 probably makes the most sense for $20/user/month.
Keep in mind that not all of your employees may require user licenses. If all they are going to be doing is viewing the SharePoint site and not editing, then you can set them up as Visitors and they don’t cost you a thing.