Lunch bags just don't come any better designed for carrying around your PBJ than this one. It's about 10" wide by 10" high by 4" deep, so there's plenty of room for your lunch. Even better, it's customizable! You can choose peanut butter with grape jelly, peanut butter with strawberry jelly, or fluffernutter (peanut butter with marshmallow fluff); the main bag can be red, brown, or black; and the strap can be peanut butter color or black. $30 from dirtsa.