Sandstorm is a platform for server-oriented and web-based applications. Sandstorm the platform is open source; anyone can run Sandstorm on their own personal server hardware. When you run Sandstorm on your own hardware, you can do anything you want with it: Sandstorm the platform is licensed under the Apache 2.0 open source license which places no restrictions on usage.
"Sandstorm for Work" refers to a set of features within Sandstorm which are especially useful when deploying Sandstorm within a business or other organization. These features are part of Sandstorm and therefore are also open source. However, in official builds, they may require a special key to unlock.
Sandstorm Development Group, Inc., the developers of Sandstorm, additionally offer a service -- the Sandstorm Support Service -- in conjuction with the Sandstorm software. This service has two parts: Automatic Updates and Priority Email Support.
Automatic Updates are provided free of charge to everyone. However, in the official builds distributed by our update server, Sandstorm for Work features can only be enabled by providing a "feature key". We provide these keys to users with a paid subscription to the Sandstorm Support Service.