FYI - NuPro cameras are a GoPro competitor targeting the water sport world (scuba, fishing, surfing, etc) that I believe is a much better camera at a lower cost and you don't need to buy cases to waterproof it.
Why would you need to buy a case for a GoPro? A GoPro comes with a dandy waterproof case included, along with rather nice video software. Add some aftermarket spare batteries + charger, maybe a few extra mounts, maybe some clip on red filters - that's only a few tens of dollars. And the only way I could imagine spending so much more as some folks have mentioned would be with a tray with a pair of real video lights. OK, I did just buy a threaded attachment plus macro lenses for my Hero Silver, and I went with the $15 version instead of the more expensive flip-on / flip-off. Maybe I'll regret going cheap, but it's a low cost experiment.
Amazon.com : Neewer 52MM Close-up Filter Set for GoPro Hero 3+/4: (1)52mm Macro Close-up Filter Set(+1, +2, +4, +10) + (1)52mm Lens Filter Ring Adapter + (1)Microfiber Cleaning Cloth + (1)Filter Carrying Pouch : Camera & Photo