I've been shooting commercial photography for years and despite any fancy gear I might have in my arsenal, I never walk on a set without at least one reflector with me. SLR Lounge put together a great tutorial showcasing the power of one of the most affordable photography tools that every photographer should learn to use.
They made a great point in the video that if you use available light and effectively, that reflectors can be used to take an awesome portrait in lieu of buying flashes. Personally, a lot of my work has a particular look created by using powerful flashes with modifiers, but I understand how some could definitely use this skill set in a creative fashion. It was really incredible what Lauri was able to create.