I got a £25 SJCAM deal (PSA on here) …
Worked perfectly well snorkelling and I even let an octopus have a play… (really)… he/she took it inside their hide and i had to rescue it. Had it down to about 30′ (which is where my ear leaks) with no issue. Jumped off a cliff with it… etc.
Quality wise it won’t make NatGeo…. or even the Hero 5 but had I lost the battle with the Octopus (or otherwise lose it) its not a big deal so long as the memories are saved.
(We have a Hero 5 as well…. just didn’t want to risk it plus to get the better quality battery is poor on the GoPro and if I dial down quality I more or less might as well use the cheap one.
Comes with all the mounts etc. to go on a helmet, chainstay etc. as well….