The Volume Purchase Program is only available in the US. Every paid app in the App Store is available for businesses to buy in volume. Free apps are excluded.
Businesses need first to create a volume purchasing account. Once enrolled, they can purchase apps on the program’s website - they aren’t using the App Store in iTunes.
Custom B2B Apps
The Volume Purchase Program also provides businesses the opportunity to purchase custom B2B apps built by third-party developers. These apps have been developed in collaboration with third-party developers to address a unique business need. Therefore they are not available to the general public for purchase. The minimum price for a custom B2B app is $9.99.
What we think
It is interesting to see that Apple is now courting enterprises with this B2B App Store. Apple has recognized that employees are using iPhones and iPads also at work. It is much more easier now for businesses to distribute custom apps within their company or to specific partners. Companies are more flexible now to create and distribute apps for enterprise customers that have custom data and process needs.
More info: apple.com Volume Purchase Program - Guide (PDF) Volume Purchase Program - FAQ