if you're willing to sacrifice some features, there's definitely a market for good gopro alternatives/competitors, and most of them are around $100. here's an example:
now, the sound sucks on this one, but really, if you want to make good videos, you should probably be doing external sound anyways. the rode smartlav is a decent lavalier mic that plugs into your cell phone for recording, so that's definitely a cheap way to get that done.
i'm in the same spot as you (low budget, but want to make decent videos) so i think this is a good solution, but i haven't tried out the above camera yet.