British Guiana 1 Cent Magenta

British Guiana 1 Cent Magenta, printed in black on magenta paper, is one of the most costly postal stamps in the world. In 1856 during a shortage of these postal stamps, a postmaster happened to ask the local newspaper to print some 1- and 4-cent stamps. Very simple in its design, the four corners of the rectangle stamps were cut to turn the shape of the stamps into that of an octagon. An only copy of this stamp was discovered by Vernon Vaughan, a teenage Scottish schoolboy, while he was looking through his uncle's letters.

Estimated Price : $850,000