Is the software that enables motion of the platform free?
The simulator software that controls the platform from Windows, FlyPT Mover, is open source and free. However, it is customary to donate to its creator to thank him for his work.
The firmware for the Motion4Sim controller, the interface between FlyPT Mover and the actuator motor controllers, is also free, and updates are included when available.
Note that using a virtual reality headset requires the use of motion compensation software, also open source, called openXR MC or openVR MC. It is also customary to donate to the creator to thank him for his work.