Great light for the money. - SureFire M640U Scout Light Pro 1000 Lumen Ultra High Output LED Weapon Light

This is hands down one of the best lights for the money. Sure you can go cheaper but when you need a light that just works, this is the one. I like that you can use it with a pic rail or mlok slots and cuts out the need for aftermarket mounts which ends up saving you a little extra over the older scout lights.