Here are some factors that can affect the value of a 1918 D Buffalo nickel:
* Condition: The overall condition of the coin is the most important factor in determining its value. A coin in excellent condition, with sharp details and no major damage, will be worth more than a coin that is worn or damaged.
* Rarity: The 1918 D Buffalo nickel is a relatively rare coin, with only about 1.2 million minted. This makes it more valuable than other Buffalo nickels from that era.
* Mintmark: The "D" mintmark indicates that the coin was minted at the Denver Mint, which is one of the reasons for its rarity.
* Numismatic Value: The numismatic value of a coin refers to its value to collectors. Some coins are more popular with collectors than others, and this can affect their value. The 1918 D Buffalo nickel is a popular coin with collectors, which can add to its value.
The exact value of a 1918 D Buffalo nickel will vary depending on the coin's specific condition, rarity, and other factors. If you have a 1918 D Buffalo nickel, you should get it professionally appraised to determine its value.