Brenda (and everyone),
I bought the same binder panels when they were on sale at JoAnns and I bought two 9" wide by about 9" deep by about 6-1/2" high clear storage boxes. I plan to cut the panels in half and store them with the stamps on them and an index card in the boxes. Unless I put the panels in page protectors, it seems some little piece of my stamp set ends up falling off when I put them in binders. I suspect I'll need more than 2 storage boxes, especially as I take more rubber stamps off their wooden blocks, but they stack and I have lots of shelving in my craft room.
I hope this description makes some sense (and I also hope it works!).