I don't believe there are any $50 dollar lights that are usefull for riding singletrack at night.
When I started trail riding I used a Night Rider Trailrat. It is probably the minimum amount of light you could use for trail riding and the cheapest light I know of that would work.
And keep in mind, you should really have a backup light with you (like a petzl headlamp or something) when you are out on the trail at night.
Some people make their own lights and instructions have been posted on this forum before. You could search here or maybe ask on the commuting forum. edit: or the lighting forum (I never knew we even had one of those)
Good luck, night riding is a blast
Last edited by C Law; 08-17-07 at 01:44 PM.