Moved to Forum: Original Link
RenderMan is now free for all non-commercial purposes, including evaluations, education, research, and personal projects. The non-commercial version of RenderMan is fully functional without watermark or limitation.
The full FAQ is here. Enjoy :)
RenderMan costs $595 USD, so if you made a movie with the free version and wanted to release the movie you'd need to pay that. Updates cost $250 USD per year. At least I think I'm understanding the pricing right https://renderman.pixar.com/general-faq