>>1115216depends on how much you want to spend
more money will get you better battery life, better video and less likely to break
however, there's some really cheap <$50 options that work good enough to use
also, make sure what you're getting either comes with a case and mounts or is compatible with 3rd party ones
gopro knock offs are nice since there's tons of cheap gopro accessories out there like cases and helmet mounts
>less than $100lighdow makes a gopro knock off for $40. I've never used one but they get good reviews
xiaomi yi makes a slightly more expensive gopro knock off as well, that's supposed to be good
>100-200contour roam is very good, although i think it got more expensive
gopro hero+ is supposed to be good
yi 4k is supposed to be good
>200+fly12 and fly6 are pretty cool, they're integrated camera + lights. expensive, but since they're also lights they're a good deal
gopro hero 3, 4, 5, depends how much you want to spend