IMO, QUANITY plays a good part in a bike's rear light system too. I am running 5 rear light, with several of them moving..

I run a Planet Bike SuperFlash Turbo on the seatpost on the rear, a SuperFlash Clone on the rear of my helmet, and two Superflash Clones on each one of my calves which are attached to to blinking reflective light strips, and sometimes a little blinky inside my sock, which is included right behind my helmet.. I think I am under $50 for all of this too.