
Joshua C. answered 07/25/19
Help Desk Technician and System Admin with 10+ Years of Experience
There are a number of different types of Volume Licensing, Open being the most common but there are others such as Educational, Government, Enterprise (for organizations of 250 users or more), etc.
VL's have to be purchased from an authorized licensing partner - CDW or other large reseller of your Microsoft Licenses. They cannot be purchased via the retail market.
You can't purchase Windows 7 VL's any more but would purchase Windows 10 which allows downgrade rights to Windows 7 or 8.
Also, if you plan on going the Windows 10 route, it sounds like you do not plan on having these machines attached to a Domain so I would just go with Windows 10 Home.
You'll be hard pressed to find volume licenses for older OS's unless you go directly to Microsoft through their Volume Licensing Center and see if they will allow for volume licensing of a legacy OS.