Please don't assume that because a coin is old, it has to be made of silver. Like all nickels except for those struck during WWII, Indian Head nickels are made of cupronickel, not silver.
There's more information at the Related Question.
a 1920 buffalo nickel is worth about 2.50 because it's not that rare
They didn't mint 1920 US silver dollars.
Average value is $3.00-$5.00.
No silver dollars were minted from 1905 to 1920 inclusive.
No such US coin exists. Silver dollars were not minted from 1905-1920.
This famous design is also frequently called an Indian head nickel. Please see the question "What is the value of a 1920 US nickel?" for more information.
a 1920 buffalo nickel is worth about 2.50 because it's not that rare
The coins are also called buffalo nickels but none of them were struck in silver.
The last V nickels were struck in 1912. 1920 is a Indian head.
The coin is called an Indian head nickel or a buffalo nickel, not a "buffalo head". It shows the entire buffalo, not just its head. Please see the question "What is the value of a 1920 US nickel?" for more information.
U.S. cents were never struck in nickel. If your coin is nickel- or silver-colored it was plated. That makes it an altered coin with no collector value.
The Buffalo/Indian Head Nickel's composition was 75% copper and 25% nickel. The only war-time silver nickels were from 1942 to 1945. A well-circulated 1920 nickel values from 5 cents to 2 dollars. If never circulated with original luster and full horn in reverse could be over $100 for a 1920-D. If the color is silver toned or shiny then it could be the original strike or has been cleaned or dipped in a cleaner.
Perhaps you mean the buffalo nickel, because Abraham Lincoln has been on the cent since 1909.
None at all, no buffalo's ever had silver
They didn't mint 1920 US silver dollars.
A 1920 Buffalo nickel is common, assuming it's circulated and has no mintmark values for coins in average circulated condition are $2.00-$8.00.
No, a 1920 Buffalo nickel is not made of silver. It is composed of a 75% copper and 25% nickel alloy. Silver was not used in the production of Buffalo nickels.