During a July 2012 auction by Heritage Auctions, a rare 1992 Lincoln penny fetched more than $20,000. At a different Heritage Auctions sale in January 2017, a different specimen fetched more than $25,000. Despite how common 1992 pennies are, this particular one was really special.
The United States Mint utilized separate dies to create proof coins for collectors and coins for circulation in the early 2000s and 1990s. A mix-up occurred at the mint in 1992, causing the reverse of the coin to be struck using a proof die instead of the dies intended for usage beginning in 1993.
This die variant is visible without a magnifying glass, but it is not readily apparent to the untrained eye. Even among numismatists and coin collectors, this coin isn't often easy to spot.
Additionally, the best coin graded by the Professional Coin Grading Service was the one that sold in January 2017. Red MS-67 is the grade given to this coin. This coin has nearly perfect, shiny surfaces with brilliant gold, fire-orange, and rose-red tones," as Heritage Auctions puts it.
There aren't many of these because they're hard to see on regular currency. Out of the total mintage of nearly 4.6 billion coins from the Philadelphia mint and 4.5 billion from the Denver mint, just 20 pieces in any grade or designation have been certified by the Professional Coin Grading Service as of this writing.