Wedding Coordinator Fees?

Hey everyone,
We have just decided to hire a wedding coordinator for our august wedding! We have no idea what the price range is for this service. She will have to contact all the vendors and be in charge of all the logistics the day of the wedding, we do not want to be bothered at all! Since it is our wedding day we figured we would have a professional instead of a guest be in charge. Do you have any idea how they charge for this?
Thanks
-Renee