Rosewill via Amazon offer the Rosewill Cree XPE-R2 300-Lumen LED Flashlight Set with Bicycle Bracket, model no. RLFL-13003, for $9.99 with free shipping. That's $20 off list and the lowest total price we could find, outside of the mention below. The flashlight features an aircraft-grade aluminum body, illumination of up to 650 feet, convex lens, and the bracket features 360-degree rotation.
A close price: Newegg offers it for $9.99 via coupon code "EMCAXKS92" plus 99 cents for shipping.