I have a few acid-free plastic storage bins that work well for loose toys, but they are all rounded-off at the edges, so are not ideal to store Transformer boxes. The rounded edges mean there is lots of wasted space, and a greater chance of the boxes getting crushed into irregular shapes. I have some masterpiece boxes, and some smaller stuff. Can anyone suggest a good brand or store to look at to get some completely square storage bins with snap-on lids? Here is an example of what I don't want... rounded bottom edges and sides that rise at an angle.