This is a lot of bags, but they're well reviewed.

http://www.amazon.com/880-Biodegradable ... roduct_top

My first thought was "why not keep using old shopping bags?" These are a good price, though.

Oops. Speaking of which, your puppy pooped in the front yard and I forgot to clean it up. Just on the west edge of that walkway to the front door. Don't step in it.