(Image Courtesy of Coin World.)
Another $1.25 Mule has come onto the market! This is one of the best known and most popular mint errors, with examples typically selling for $75,000 to $150,000. Simply defined, a mule is a coin which was struck with the dies of two different coin denominations.
Such a coin has one denomination on one side and another denomination on the other. This has only occurred on a handful of U.S. coins, and so they are excessively rare and therefore expensive. For most collectors, a coin such as this will always be a "dream coin", and not affordable, and instead most collectors have to get a foreign coin mule, which can typically be purchased for under $500. Still, coins like this are the error coin hobbies version of a 1804 dollar or a 1913 v-nickel, and are the ultimate trophy error coins, which rightfully get a lot of attention when they come onto the market. Here's is a Coin World article with more information about the sale: http://www.coinworld.com/news/us-coins/2016/07/collector-buys-11th-of-15-known-mule-errors.html