GearsXS via eBay offers this i-Zoom Wireless Motion Sensor 7-LED Safety Light, model no. WMSL-1612, for $11.99 with free shipping. That's tied with our mention from two weeks ago and the lowest total price we could find by $7. It features motion detection up to 15 feet away, casts light up to 10 feet, and is weather-resistant. It requires four AA batteries (not included).
Update: Specs corrected.