One software license is required per developer.
Run-time royalty free.

Studio Controls for .NET Subscription: Includes support, new updates, new upgrades and new controls added to Studio Controls for .NET for one year.

Important: Please note that there may be a delay before you can use this software as this product requires activation. Also, please, note that 1 Developer License will entitle a single developer to activate the software on a maximum of two machines for their own use.