What is 1921 Silver dollar with a lady head worth?

The lady is Miss Liberty, as in "Statue of ..."

Two types of dollar coin were minted in 1921 so it's important to know which you have. There's more information at the Related Questions: if the coin has a spread-wing eagle on the back see the question about Morgan dollars. If it has the Word PEACE under the eagle, see the question about Peace dollars.