I have a Light & Motion Vega. It's more than you wanted to spend - $180 at REI. But lights are safety equipment. The burn time is anywhere between 2 and 8 hours.

The high setting is bright enough that I can descend at good clip on the road.

I use the low setting at dusk, when I'm climbing or there is some other light source, street lights, the moon, another rider...

We never found a cheaper light that we felt was worth the money.

V.