If you have a backpack and a GoPro camera, combining the two should be an easy decision. I even toyed with the idea of mounting it using a powerful magnet.
DIY options aside, it would be hard to beat this strap clamp from AGPtEK (Amazon). Although the price seems to have increased slightly to $6.99 since I bought it, it’s still seems like a solidly-constructed mount, with a very powerful clamp. The spring is powerful enough that unless my hand was positioned correctly, I wasn’t able to get it off!
Per one of the reviews on Amazon, this clamp is meant to be used on cloth, not metal, so don’t expect great results on that type of surface. On the other hand, you can apparently use it on a baseball hat if rotated the correct way, so that’s another option. Be sure to check out my full “AGPtEK GoPro Backpack Mount Review” below (it’s not that long)!
As you probably noticed, I’m using a GoPro Hero Session (or Hero 4 Session) for this review. I really love this camera, able to record audio and get wet without even using a shell. Check out my review here.