A storage bag has first and second side surfaces, and a sealable and an unsealable opening. A bottom end of the bag is movable between a flat configuration with the first and second side surfaces positioned adjacent to each other, and an expanded configuration with the first and second side surfaces being spaced from each other. Shape retaining strips are provided adjacent to the opening that can maintain the shape of the opening. The shape retaining strips are capable of maintaining the opening of the bag such that a distance between the first and second side surfaces at the top end of the bag is about equal to the distance between the first and second side surfaces at the bottom end of the bag.