Been looking for a good messenger bag for my MacBook. Finally found it. And got a good deal on Ebay for it as well. It costs $59.95 on the Apple Store. The Ebay store, although, sells it for $35.00. Here’s a pic:
Incase Nylon Sleeve with Handles for 13-inch MacBook
It seems to have everything I need. My MacBook, the adaptor, and my sandwiches will fit perfectly in this bag.