I is possible to make Volume App Purchases – so you can buy license to an App at the Windows Store for Business and distribute it to your AzureAD users.

Windows Store for Business overview https://technet.microsoft.com/en-us/itpro/windows/whats-new/windows-store-for-business-overview?f=255&MSPPError=-2147217396

First sign in to your Windows Store for Business

Use your WsfB Admin account

Go to Settings –> Account information

Select Show my payment options

Add a new payment method

Enter your credit card information

Click Next

Verify your Credit Card information is correct

Click Save

Click Close

Fin the App you want to buy

Select Buy now

Enter Quantity

Click Next

Verify your information

Select Buy

Click Close

Add the app to private store

In the private store you can now see the “Add in progress” – this can take up to 24 hours.
After that you can deploy the app to users from Windows Store for Business or from your management tools.