Light & Motion has dropped the price on some older models after introducing some newer lights with more power and/or longer run time. So the Urban 350 is now around $30-$35. Very good value. Several friends use those.
If the Urban 500 drops to the sub-$50 mark it'll be another good value for this thread. Now that Light & Motion has basically upgraded the Urban 500 to the Rando 500 with longer running battery, they might drop the price on the original version.