I found them at Walmart... and with our Bug In stuff stored in a Rubbermaid tub, I'm using them for storing dried food supplies & mixes. The food is in Ziplock freezer bags and stuffed into the Lock containers. They make the Rubbermaid Tub more organized, and the lock containers seem to be holding up well.
I found a knock-off version of them at the local 99 cent store. No where near as durable, but they work to hold misc. stuff (small sewing supplies, etc.).
-T