I want to buy my kids reusable sandwich bags for their lunch boxes. So I did a little Google search and spent waaaaaaay too long looking through options.
I think I've decided one of these at the Container Store:
But you can see others at The Might Nest, Lunchskins, Reusies, WasteNot Saks, SnackTaxi, Jaq Jaq Bird, Itzy Ritzy, Kid Konserve, Wrap-N-Mat (or here), EasyLunchBoxes.com, Goodbyn, and Lock & Lock Lunch Set.
And, this is a great blog post on Stephmodo about going trash free.