If you go through a lot of Tupperware or plastic food containers you may want to consider buying a set of glass containers with lids. Glass containers like the Pyrex Bake, Store and Serve set may cost a little more than your cheap plastic containers bought at the Dollar store but you will find that glass containers, if properly taken care of, will last for years and years. Making them cheaper in the long run.
Glass containers with lids:
Glass containers with lids pictured: Pyrex Bake, Serve And Store Sets, six pieces.
Also of interest: Kinetic Go Green Premium Nano Silver 14 Piece Food Storage Container Set (Includes Lids and Containers) / Libbey 6-1/2-Ounce Small Bowls with Plastic Lids, 8-Piece Set / Pyrex 6022369 Storage 14-Piece Round Set, Clear with Blue Lids