GoPro's Hero line of cameras have become the go-to action cameras, but they can get pretty pricey. If you want something just as good, you may want to check out YI's 4K Sports and Action Video Camera. Amazon currently has the US model in White Pearl for just $158.99 with a coupon code, which is just over $90 off the MSRP.
As you might be able to tell from the name, the YI 4K is capable of shooting 4K footage at 30fps with its Sony IMX377 12MP, f/2.8 155-degree wide-angle lens. (For reference, the IMX377 is also used in the Nexus 5X and 6P, as well as the HTC 10.) It can also shoot 1080p sat up to 120fps and 720p and up to 240fps. It sports a 2.19" 360p LCD touchscreen for previews, and it's powered by an Ambarella A9SE75 chip. The battery is a 1400mAh unit that can record up to 120 minutes of 4K video on one charge. Not bad, especially for the price.
If you want a YI 4K of your very own, go to the source link below. Make sure you select "YI Technology" as the seller, and you'll need to use code YI4KWNX7 at checkout to score that $158.99 price. You'll get free two-day shipping if you're a Prime member as well.