A sick setup for around 600 might be to get any cheap HD camcorder and Century Optics Ultra Fisheye Converter.
Buy a Drift Innovation HD cam if you're think about the POV route. I shoot hand-held more than I use them as helmet cams:
https://www.mypov360.com/snowboarding-pov/ (note those vids were shot on the $149 Standard Def version)