A couple years ago, when the original Robosapien robot, created by Mark Tilden, went on sale, there were no third party products. Actually, at that point, no one outside of the WowWee Robotics labs knew enough about the robot to even begin hacking it, or creating new software and accessories for it.
We bought one, and are very glad we did. Figuring out how to control it from our PC was a significant challenge that taught us a lot, though we wouldn't want to try doing it from scratch again. Fortunately now there are several million of the popular Robosapien robots out there, along with other robots in the series, like the RoboRaptor, and RoboPet. And, there are a number of third party solutions for Robosapien fans and addicts to chose from.