If you had a real budget, Id say the light&motion Stella 200L.
For a low budget, not sure you can get anything really good, Id be mainly concerned with being visible to others. There are sub-$50 lights out there, Id probably look for the one that takes the largest number of batteries, and has the most, brightest LEDs. Id then buy low-drain AA rechargable batteries and a slow charger to keep the economics of use up.
There are some tiny LED lights that use a rechargable li-battery inside, which charges from a AA when not in use. THey are cheap - less than $50 for a few of them, red and white. Very bright for good visibility. Cant recall the name though - but likely good things to clip on yourself.