The "S" mint mark indicates it was struck in San Francisco. Since the mid-1970s San Francisco has only struck coins for inclusion in proof sets sold to collectors.
If your dime is still in its protective package it's worth about 40 cents. If it was found in change someone took it out of its package and spent it, which means it effectively has no extra value. Still, it's not every day you find proof coins in circulation so it would at least make an interesting conversation piece.
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Most are valued at $4.00-$6.00
The 1948 Roosevelt dime is very common. Most are only valued for the silver about $2.00.
A 1964 US dime is so common most are valued only for the silver at about a dollar.
The 1941 Mercury dime is very common, most are valued at $2.00 just for the silver.
1943 is a very common Mercury Head dime. Most are only valued for the silver, about $2.00.
1937 is a very common Mercury Head dime. Most are only valued for the silver, about $2.00.
A 1951 Roosevelt dime is very common, most are only valued for the silver in them, about $1.35.
A 1937 Mercury head dime is common, most are valued just for the silver about $3.00.
Most are only valued for the silver, about $2.00.
A 1963 Roosevelt dime is very common. Most are only valued for the silver, about $2.00.
7-2-11>>> The last Mercury dime was struck in 1945. A 1958 dime is a Roosevelt dime (1946 to date) and is common, most are only valued for the silver, about $2.00