http://furryball.aaa-studio.eu/products/freeVersion.html

FurryBall 4.x - Free Version

FREE version is without watermark now!

You can use FurryBall FREE version for NON-Commercial use like final render.
(include evaluations, personal learning, experimentation, research, and personal images and animations)

Free version restrictions

• the licence NEVER expires
  
• free version must be activated and reactivated over internet
• Resolution limit is Full HD (1920x1080)
• Final output render is slowed down 3x
  (the render actually completes in the usual time, but the watermark isn’t removed until the time limit)
  (for example: If your render time is 3 min, your final render will finish in 3 min, but watermark will be removed from image after another 6 min.)
• NO slow down for rendering in viewport
  
• this version CAN'T be used for commercial purposes
• reactivation is required after each 30 days of usage