Some pennies are valuable because they're rare. Rare collectable pennies include the half-cent, the large cent, the Indian penny and the wheat penny. Other types of pennies are collectable because they have minting defects that appeal to collectors.
The 1943 penny is one of the most valuable pennies. It's rare because it was struck in a copper-zinc coated steel alloy, a combination of metal no other U.S. coin has. "Wheat" pennies with stalks of wheat framing the "One Cent" minted on the back of the coin are becoming increasingly hard to find.
Defect or error coins slip past mint employees and end up in circulation despite their imperfections. Such defects include blank pennies, off-centre pennies, missing mint-mark, double struck coins and coins that have bubbles, crumples, rips or peels. Other minting errors include mistakes in design, metal type or coin type.
Only about 40 1943 pennies still exist. Due to the extreme rarity, the penny commands a high price. According to the U.S. Mint, one sold for £6,500 in 1981 and another sold for £53,625 in 1996.