[Accessory] Stamp Mount [Price Range] $8 per package (>6 mounts depending on size) of 215mm mounts average [Description] 
They are the accessory of choice to store and affix stamps that are expensive and/or mint. Hinges have the disadvantage that hinge marks are left behind on mint stamps. Further, collectors prefer MNH (Mint Never Hinged) stamps and which explains the premium associated with them.