BuyDig offers the Cree LED Bike Light bundled with a 9-LED Safety Tail Light for $24.99. Coupon code "LETSRIDE1" cuts it to $10.99. With free shipping, that's $39 off and the lowest price we could find. The flashlight purports to last up to 100,000 hours, and requires three AAA batteries (included). The tail light has seven flash modes and requires two AAA batteries (not included).
It's also available in a 2-pack for $18.99 with free shipping after coupon code "LETSRIDE2". That's $41 off list and another price low.