I use the foam core boards from the dollar store also. I was getting them at Walmart and they are nicer but more expensive. You get quite a few from each board, depending on the size you cut. I also have the comic book boards too. I love having them all nice and neat and where I can see what I have. I also have tubs full in the closet and in my storage, but I over buy because I have no idea what is in those bins most of the time.