The Most Expensive Stamps

1856 3 skilling of Sweden
This stamp was bought for 2.2 million dollars on November 8, 1996 at auction in Switzerland. It is so rare because of its color. The 3 skilling usually is blue-green. This unusual color is probably due to an error of the man in charge of impression who may have put the sheet for the 3 skilling while the press was prepped for the yellow eight skilling. This stamp has changed hands multiple times and has been at one time in possession of the King Carol II of Romania. Before the 3 skilling, the most expensive stamp was the One cent magenta.
The One cent magenta
The One cent magenta was issued in 1856 in British Guyana when the isle run out of stamps. Stamps had to be printed in emergency and so was born the one cent magenta. It is very much a makeshift stamp, of poor print quality, but it was to become one of the most expensive stamps in the world. The only one cent magenta stamp left was (re)discovered in 1873 by a Scottish schoolboy.
The 1FR Vermillion
This French stamp was issued on January 2 1849 and was used on letters weighing from 15 to 100g. This stamp was only short lived because it was recalled to produce a variant in another color. Indeed the 1FR vermillion was often confused by people with another popular stamp at the time.
The Penny Black
Ok so it might not be the most expensive stamp in the world but it is arguably the most famous. The Penny Black was, after all, the first postage stamp ever issued. The Penny Black was first issued in 1840 to reflect the new British postage system: from then on, cost of postage was to be paid by the sender and not the receiver as was the case before. 112 000 letters were posted on the first day of the introduction of the Penny Black and 168 million in 1840 alone, proof that sending letters was know at the reach of many and to be honest, can we put a price on that?