If you are referring to the Scarlet Skunk Cleaner Shrimp, yes they are scavengers too, so they will help eat up leftover food in the tank.
This shrimp is popular among reefers, because they not only can help "clean" the fishes of dean skin and some parasites (if the fish allow), they are part of the clean up crew too.
I've seen prices ranging from $6-$12 depending where you get them.