A free, open-source 3D creation suite covering modeling, animation, rendering, and video editing.
Blender is developed by the nonprofit Blender Foundation and released under the GPL. It supports the full 3D pipeline - modeling, sculpting, rigging, animation, simulation, rendering, compositing - plus motion tracking and basic video editing.
Yes. It is open-source software and work you create with it is yours to use commercially.
Yes, official builds are available for all three platforms.
Information and links are accurate as of the time of writing and may change. Always verify on the official site. This is an independent guide, not affiliated with the listed services.