I have a hero 3+ and white, The white is cheap but I haven't tried it in the higher quality settings and isn't "wide screen". My hero 3+ is meh during the day in 1080p at 60fps but its crappy compared to the hero4. Depends on what you want to do with it. If your trying to read license plates after people try and side swipe you, hero 4. Hero 3 if you just want video evidence of ricky bobby shenanigans. Night time sucks on the hero 3+ unless there is a night mode.
Both were "cheaper". If you want mega cheap. Mobius.
White came in at $149 at the walmarts.
hero3+ came as a package deal with other accessories for $300ish
Amazon is definitely a good place to start as you could get a little package deal going.
hero 3+ at night.
http://www.youtube.com/watch?v=gpJBDH_HflA&hd=1