Our little town still has plastic bags when you go to the grocery store. I try to bring my own reusable but most of the time I forget. These little bags are pretty handy in the diaper trash. They can take over your house though pretty quickly.
I have found that using an empty tissue box as a storage container for these little things is pretty awesome. So many fit in the box and then when the container in the Kidster room runs out of bags I just refill them from this box.