I just bought DS a Tupperware cooler bag that came with a sandwich keeper. I like it because the sandwich keeper will keep the bread getting wet if I were to put a frozen popper or something in and the bag is made so that the dampness doesn't come through to the outside. It was $29.95 for both. They have it currently in green and yellow I think they were..

Oh and I forgot to add its made for kids bags so is smaller than usual cooler bags.