Here is a secret for "permanent free-ish." Because R20 is legacy software that cannot be upgraded to R21 or newer via Maxon’s new subscription model, users sometimes sell their permanent licenses.
While Cinema 4D R20 is a paid professional software, you can access it or its features through a few legitimate "free" methods and resources: Legitimate Free Access cinema 4d r20 free
Cinema 4D vs. Blender: Choosing the Right 3D Software | RebusFarm Here is a secret for "permanent free-ish
The beginning of the shift toward a more flexible shading workflow. Can You Get Cinema 4D R20 for Free? cinema 4d r20 free