On a Christmas shopping trip to NYC, I found this food storage container at Pearl River Mart. The store is located in Soho and sells all sorts of Chinese imports, most very reasonably priced. They call this item a "lunch box."
It is about 7 inches long, 5 inches wide and 3 inches deep, and I'm finding it very handy for holding my applique supplies. The lid is held in place with clips to each side. Under the lid is an upper tray about an inch deep, perfect for flatter items.
Under the tray is a deeper space that holds spools of thread and my travel pincushion.
This little item costs less than $6. They also have bigger stacked versions, inlcuding colorful melamine versions they call tiffin lunch boxes. Sewists and quilters could put them to good use too.