BikePakUSA via eBay offers the BV Bicycle Super Bright LED Headlight / Taillight Set, model no. BV-L801, for $8.99 with free shipping. That's the lowest price we could find by $8, outside of the mention below. It features a 5-LED headlight and 3-LED taillight, both with quick-release mounts. Six AAA batteries are required, but not included.
A close price: Amazon charges $9.19 with free shipping for Prime members.