360 videos look much better when they're stabilized. The BINKO Videook VS-GO is a video stabilizer with a non-motorized gimbal and counterweight, similar in design to the StayblCam, but at a lower price.
The Videook uses a free-moving gimbal and a counterweight. The top of the Videook is a 1/4-20 tripod screw that can be used with many cameras such as the Ricoh Theta and Samsung Gear 360. There is also an adapter for a smartphone and for a GoPro camera.
Here is a video describing the Videook's features:
Here is a video testing the Videook's effectiveness (thanks to auntifranny):
The Videook is similar in design to the Stayblcam. One difference is that the StayblCam's phone adapter can be used for a smartphone in vertical orientation, such as when using the Insta360 Nano, whereas the phone adapter on the Videook is only for horizontal orientation. On the other hand, the Videook is flat at the bottom, which allows it to stand on a flat surface.
The Binko stabilizer is available on Amazon for $49.99, substantially less than the Stayblcam ($74.95 + shipping).