My friend Vicki, in Pacific Grove, CA, is part of a program to disallow plastic bags within the city limits. Plastic bags are a huge problem there--they end up in Monterey Bay & kill all sorts of wildlife, mostly sea turtles & sea otters. So here are a few ideas for making your own re-usable shopping bag. The first is how to turn an old t-shirt into a shopping bag. And the other site is a list of 50+ different sites that have "how-to" instructions to make your own shopping bag, so you don't need to make the paper or plastic decision ever again.
Recycle a T-Shirt into a shopping bag! Instructions here.
And another site with many patterns for making your own shopping (or book) bag.