So which one to pick?
The original GoPro works great but pricey. about $55.00 US.
but the if you dont mind the brand...
Getting a little fancier than the previous 2 but not more than the original, comes the Spivo 360, I have seen the advertisement of these and seems pretty neat what they do.
And lastly, if you don't care about brand, utility and use it for short periods of time (if using the phone as a monitor), here comes the Telesin. Made in aluminum, but includes a holder for your phone, as a preview monitor, in case you don't have the GoPro Silver version which comes with a rear monitor. And for just over $10.00 US I think is worth it.