We have used sand as I base layer for straw bedding for years for sheep and cattle but I myself have never used it in the coop jus because it's convenient to buy the sawdust in bales that I can carry comfortably over to the coop. As said before they were housed full time I never had anything other than the concrete floor. Which was cleaned weekly.
I wonder how he does it at that price but it's the same as all of us. With very little margins I suppose. I can't say I'm making a fortune from egg production. But that's not why we do it.