I made these cute little lunch bags from a free tutorial on a blog called "Pink Penguin". They are fun to make and I really liked the tutorial because each step had pictures of how to do it.
I used quilting fabric with a medium weight fusible interfacing. This seemed to work well. When sewing the rim on and the lining to the outside I used a walking foot. It was quite thick as I was going through quite a few layers but it was quite easy because of the walking foot.