I made this caddy using the video from Sewspire below. I had some pieced scraps that were sitting in my sewing closet and they worked well for the sides of the caddy.
I cut the squares 5 inches and the rectangles 5" by 10". I used heavyweight interfacing only on the outside pieces and the handles (which I made from 3" by 8" strips). This made quite a sturdy caddy.