One of my favorite web sites is Gizmag. Each weekday they show some of the latest tech stuff. One of today's features was a little video camera that was about $25. Actually, it's about $17US plus about $8 shipping from Hong Kong. The editors were most surprised at the quality of the video footage and posted some of a guy in the UK doing a bit of riding.
I bought one - too cheap to resist ( the camera, not me ).
On Ebay, there is just one "Buy it Now" camera but a ton more if you want to piss around with an auction on something so cheap.