So I had been storing my classroom books in these cardboard scholastic things the last few years.
They were really beat up and falling apart, but it is what I had:
I had some milk crates in my classroom so I zip tied two together and then loose leaf rings to hang baskets to the sides.
I have three of these sets and really like them. They are super sturdy and I can put books in the baskets to spotlight!
I think they would be even prettier with colorful milk crates, but I didn't want to invest in colorful until I knew it was functional!