I bought 2 of these a few months ago and they are great.
BikePakmart - Super Bright 1-Watt Headlight, 1/2 Watt Taillight, Safety Light Set, Quick-Release, Weather Resistant the tail light is identical to the planet bike super flash and parts are interchangeable. It also includes a nice headlight that has about a 100 lumen output that is usable for limited night riding or as a day-time strobe. Both use a a a batteries. I bought the sets for 13 bucks but they went up to 29 recently. Maybe they were mispriced, but even at current price you get à super flash with a free headlight included. The tail light is fantastic and the headlight is great for daytime flashing or as a limited use night riding light.