Reisenthel Mini Maxi Ladyshopper
I loved the Reisenthel Mini Maxi Ladyshopper ($19) long before shopping bags were cool. The teeny-tiny case clips to the diaper bag and holds a good-sized nylon shopping bag that can carry up to 20 pounds of baby gadgets! You can either fold the bag neatly or shove it into the case with your thumbs (our preferred method) on the fly.
Note: The Ladyshopper is now available at TouchofEurope.net in eight colors. They carry a nice selection of other Reisenthal products as well.