An envelope has front panel and a back panel, the front panel and the back panel joined along three edges and open along a fourth edge to provide an opening to an interior of the envelope. A foldable flap extends from the front panel to close the opening. The front panel, back panel and flap are formed of a compostable plastic film, and the envelope is configured to be entirely compostable as-is by a recipient.

An envelope has front panel and a back panel, the front panel and the back panel joined along three edges and open along a fourth edge to provide an opening to an interior of the envelope. A foldable flap extends from the front panel to close the opening. The front panel, back panel and flap are formed of a compostable plastic film, and the envelope is configured to be entirely compostable as-is by a recipient.

An envelope has front panel and a back panel, the front panel and the back panel joined along three edges and open along a fourth edge to provide an opening to an interior of the envelope. A foldable flap extends from the front panel to close the opening. The front panel, back panel and flap are formed of a compostable plastic film, and the envelope is configured to be entirely compostable as-is by a recipient.

A package compliant with a postal service flats mail class includes at least one flat package substrate comprising a uniform edge thickness about one of a longitudinal dimension and a shorter dimension and configured to be flexible parallel to the one dimension and adapted to receive an integral item parallel to the one dimension. The package also includes an integral item at least one of interleaved within the substrate and wrapped around the substrate parallel to the one dimension and adapted to provide flexibility to the other of the two dimensions based on the interleaving and the wrapping and provide a uniform edge thickness to the other of the two dimensions. Furthermore, a receiving package is structured to receive and secure together the integral item and the flat package substrate and provide a uniform thickness and the uniform edge dimensions and be flexible about both the two dimensions.

An envelope has front panel and a back panel, the front panel and the back panel joined along three edges and open along a fourth edge to provide an opening to an interior of the envelope. A foldable flap extends from the front panel to close the opening. The front panel, back panel and flap are formed of a compostable plastic film, and the envelope is configured to be entirely compostable as-is by a recipient.

An envelope has front panel and a back panel, the front panel and the back panel joined along three edges and open along a fourth edge to provide an opening to an interior of the envelope. A foldable flap extends from the front panel to close the opening. The front panel, back panel and flap are formed of a compostable plastic film, and the envelope is configured to be entirely compostable as-is by a recipient.

A trading card mailer incorporating an envelope having left and right U transitions; left and right sleeves within the envelope, wherein each sleeve among left and right sleeves has a left side and a right side, and wherein the right side of the left sleeve abuts the left side of the right sleeve to form a seam; a flexible card having left and right ends, the flexible card being received within the envelope; and left and right anchors, wherein the left anchor includes a left U transition and card end combination or includes a left adhesive bond and left sleeve combination, and wherein the right anchor includes a right U transition and card end combination or includes a right adhesive bond and right seam combination.

A trading card mailer incorporating an envelope having left and right U transitions; left and right sleeves within the envelope, wherein each sleeve among left and right sleeves has a left side and a right side, and wherein the right side of the left sleeve abuts the left side of the right sleeve to form a seam; a flexible card having left and right ends, the flexible card being received within the envelope; and left and right anchors, wherein the left anchor includes a left U transition and card end combination or includes a left adhesive bond and left sleeve combination, and wherein the right anchor includes a right U transition and card end combination or includes a right adhesive bond and right seam combination.