What is the value of a 1938 US silver dollar?

The last 90% U.S. silver dollars were minted in 1935.

No dollar coins were minted again until 1971 and all of those are either copper-nickel or brass.

If you turn the coin over and it has the Words HALF DOLLAR on the back, that's a good indication it's not a silver dollar but rather a silver 50¢ coin. If so, please see the Related Question for more information.