Surefire is the largest maker of powerful tactical flashlights for weapons and other gear. They offer 20% off to military personnel by ordering via phone.
Straight from their webpage:
Military discount – On everything except batteries we give a 20% discount off retail price to active-duty military, military reserve, and National Guard personnel. To order, call SureFire at 1-800-828-8809, press 1, and identify yourself as military.
Check out their products at https://www.surefire.com.