I'm using bins for the first time this year. I have used ziplocs for the last couple of years...time for a change! I found these great collapsible bins at Dollar Tree. The come in yellow, green, blue, and red.

I was leary of them at first because they felt a bit flimsy. I asked the manager to show me how to UN collapse them

!! I told her what I was using them for and she proceeded to go to the children's book section. She took a PILE of books from the shelf and put them in the basket. We were both very surprised how sturdy it was! I bought 25 of them!!

The other thing I liked about them is that they will accomodate larger books and the sides are straight up and down. Some bins have 2 slanted sides which inhibits larger books from fitting.

Hope this helps!