Fortunately Microsoft has a pretty straight forward distribution model.  First up is Original Equipment Manufacturer or OEM.  These are companies that obtain licensing directly from Microsoft and install the software on the PC’s they sell.  Next are distributers. Distributors fill orders for licenses received from resellers.  Resellers include system builders, retailers who sell Open Licensing and Fully Packaged Products or FPP (if you bought MS Office at Best Buy you would be getting FPP) and lastly Authorized Education Resellers/AER.   

Larger companies who purchase Select or Enterprise Agreements will require other distribution channels.  Large Account Resellers or LAR’s are authorized to sell Select and Select Plus licenses.  Enterprise Software Advisors or ESA’s are authorized to offer Enterprise Agreement and Enterprise Subscription Agreements.  In some cases Microsoft will work directly with the customer to set pricing. 

For small organizations I would recommend looking at:

1)      Open Value

2)      Open Value Subscription

3)      Open License

Midsize Companies:

1)      Open Value

2)      Open Value Subscription

3)      Select Plus

4)      Enterprise Agreement

Large Companies:

1)      Enterprise Agreement

2)      Enterprise Subscription Agreement

3)      Select Plus