Here's a clever idea from Better Homes and Gardens:
"Scope out old dresser drawers to repurpose as another kind of bedroom storage. By attaching casters to the bottoms of the drawers, you'll have a set of underbed storage units, making the space beneath the bed good for more than just dust bunnies."
More DIY storage ideas:
DIY Scarf Storage
Plastic Bags are Messy - Box Them Up!
What to Do with Those Dry Cleaner Hangers? - Make a DIY Shoe Rack