They are relatively inexpensive but most importantly are an easy bait to use, as you cast them out and retrieve them back. There are about a billion different ones to choose from but Mepps, Blue Fox and Rooster Tail have a great selection to choose from.
I would encourage all of you to have a few in your tackle boxes, in different sizes as well, the can truly make a difference when the bite is tough and you need a simple looking bait.
They mostly resemble a scurrying bait fish in the water or a variety of insects that have potentially ended up in the water and are trying to take flight again.
If you know anyone looking for some easy start out baits refer them to this video as I am sure they will definitely find it helpful.