"FIVE CENTS" on Raised Ground &In Recess
The first batch of buffalo nickels from 1913 feature the words "FIVE CENTS" on a mound below the feet of the bison. The mound was removed later in the year and on all subsequent releases. All other copies of the buffalo nickel feature the words "FIVE CENTS" in a recess below the bison's feet as a result. About half of each variety was minted in 1913, so neither carries a premium price over the other variety.
1916 Double Die Obverse
An unknown quantity of 1916 buffalo nickels feature a double die obverse, meaning they were double-stamped by accident. You can see the double stamp clearly by looking at the date, which can be seen twice on this variety, with each "1916" slightly offset from the other. This hard-to-find error coin can sell for more than $2,000 at time of publication in good (G-4) condition. By comparison, a non-error coin from this year tends to sell for $5 to $15 in the same condition.
1918 "8" Over "7"
Some copies of the 1918 buffalo nickel minted in Denver feature an "8" stamped over the "7" in the last digit of the date. This type of error was common among earlier U.S. coins when some copies were accidentally struck with the wrong date, and the mistake was later corrected. This variety, however, is relatively hard to find. An unknown number of these coins are on the market, with this variety often selling for more than $1,000 in good condition at time of publication.
Three-Legged Bison
Some of the 1936 and 1937 buffalo nickel coins minted in Denver depict a bison missing a front leg due to some error in the dies. Like the other buffalo nickel varieties, it's not known exactly how many copies exist. This error tends to be more common than the double-stamped coins as the three-legged bison error sells for about $500 to $750 in good condition at time of publication.