What is the value of a 1939 Mercury dime?

1939 is not a rare date for Mercury dimes. In circulated condition, its value is based only on the silver it contains - as of 07/2011 about $3 to $3.50.

If it's in new or nearly new condition, look on the back of the coin to see if there's a small mint mark letter next to the E in ONE. It may be blank or there may be a D or S. (The W on the front of the coin is the designer's monogram and not a mint mark.)

Numismedia lists the following approximate retail values :

No mint mark (Philadelphia):

Almost no wear - $6

Uncirculated - $10 to $325 depending on quality

"D" mint mark (Denver):

Almost no wear - $6

Uncirculated - $12 to $425

"S" mint mark (San Francisco):

Slightly worn - $4

Almost no wear - $10

Uncirculated - $16 to $189

DISCLAIMER: The retail values quoted are the best available as of the date shown, but may vary significantly due to changes in the precious metals market. Also the wholesale (buying) price of a coin will be less than the selling (retail) price. A reputable coin dealer will be able to give a more accurate valuation based on inspection of the coin.