there are two ways to get OctaneRender, Frank:
a. by buying licence for
standalone application & choosing plugin You need one (no limitations)
or
b. getting
subscription 20$/month (with limitation of using up to two GPUs & no network rendering option)
Standalone is fully fledged application & I would try it, before getting into plugin, but if You prefer to stay inside host application that's another choice You have. Subscription service is cheaper to start if You wish to try without demo limitations =) Please let me know if You would have any other questions ;)