Chaos Group - Render Node 3.x license (single price)
Extra Render Node for V-Ray.
V-Ray for Blender
With V-Ray 3.x Render Node comes V-Ray Standalone, a full-featured command-line renderer that supports native .vrscene format, and is the core of V-Ray for Blender (free). If you use Blender and want to render professionally it is V-Ray Render Node you are looking for.