The 1943 copper-alloy penny was a mistake. The only known 1943 copper penny produced in the Denver mint sold for $1.7 million in 2010, while other 1943 copper pennies are worth in excess of $50,000, depending on condition. During World War II, the war effort needed copper and zinc, so the 1943 penny featured steel, but a few copper-alloy blanks were still in the hoppers at the mints. Because of the value, enterprising forgers cover 1943 steel pennies with a layer of copper. A magnet reveals a forgery; if the penny sticks, it is a fake.
The 1944 steel penny is also a mistake, with a value sometimes approaching $100,000, depending on condition. The U.S. Mint changed the coin's composition back from steel to a modified copper alloy made from used shell casings, but some steel blanks left in the hopper resulted in rare 1944 steel pennies.
With only 2,000 coins made, even a worn 1856 Flying Eagle is worth more than $7,000, as of 2015. The value increases according to the coin's condition, with a pristine example valued up to $85,000.
The obverse, or "heads," side of some 1969 pennies struck in San Francisco has a double image. It is easiest to see when examining the type on the penny with a strong magnifying glass. The mint strikes the "S" separately, so it does not have a double image. A 1969-S Doubled Die Obverse penny graded at "About Uncirculated 58" sold for $28,200 in 2013.
The reverse side of a few 1992-D Close "AM" Reverse pennies struck with the die intended for the 1993 pennies shows the first two letters of "America" so close together that the bottoms of the two letters nearly touch. In 2012, one sold for $20,700 at the Florida United Numismatists summer convention.
This 1873 Indian Head penny features a doubled "Liberty" in the Indian headband. It also has a smaller opening in the "3" in the date, called a "closed 3." Values for the 1873 Doubled Liberty "Closed 3" Indian Head penny range from approximately $350 to $13,000, depending on condition.
The 1877 Indian Head penny's value is due to its rarity. In general, the mints strike millions of pennies every year, but in 1877, they struck only 852,500 pennies. Depending on the penny's condition, value ranges from $880 to $2,500.
Approximately 24,000 of the 1955 pennies have a double image on the obverse side. Although the U.S. Mint knew about the doubled die, it released the pennies with the error. First discovered in a New England vending machine, these pennies are highly sought by collectors. 1955 Doubled Die Obverse pennies in exceptional condition can exceed $10,000 at auction.
The 1970-S Doubled Die Obverse penny is especially strong in the first three letters of "Liberty" and "In God We Trust." The doubling should only appear on the obverse side, if it is on both sides, it is a double struck coin and not valuable. The 1970-S doubled die pennies range in value from $1,000 to $5,000 or more, making them an ideal addition for a budding collector on a modest budget.
The 1922 wheat penny should have a "D" under the date, indicating that it is from the Denver mint. Approximately 15,000 to 20,000 1922 pennies are missing the "D," although all 1922 pennies came from Denver. The value of pennies with a missing "D" and a strong reverse side often exceeds $1,000.