What are the best action cameras around $100?

While the camera itself, even if it's made of plastic, doesn't feel very flimsy / cheap, but not only does the thin plastic cover for the battery not look very promising it is even more concerning that there is no cover for any of the ports or the memory card slot. If you're looking to use this in some more active areas, I would recommend using the included waterproof / protective case. You'll most likely lose the audio but the camera will be much better protected from the elements.