With a little careful shopping you should be able to find a Planet Bike Blaze 2W front and Superflash rear lights for around $60.
Rechargable batteries + charger will still come in under you budget.
They are great basic commuter lights. The headlight has a flashing mode for daytime, and the quick-release brackets make it very easy to take the lights with you when you lock up.

http://www.rei.com/product/797836/pl...ont-bike-light
http://www.rei.com/product/772679/pl...ear-bike-light
(wait for a 20% off sale at REI... )

http://www.amazon.com/Planet-Bike-Bl.../dp/B0015R1NE4
(Amazon prices change constantly. I got my 2W Blaze for $39.00)