That's not a mint mark on the obverse. It's the monogram of the coin's designer, Anthony de Francisci. Look closely and you'll see an intertwined A and F. Peace dollars issued at San Francisco and Denver all have their mint marks located on the coin's reverse, just above the eagle's tail feathers and underneath the word ONE. Coins struck at Philadelphia do not have a mint mark.
$27.
The Morgan Silver Dollar can range from $25 to $70, and the Peace Silver Dollar from $50 to $300.
It's actually called a Peace dollar. Its value is around $14 to $16 for its silver content.
The first Peace dollars were struck in 1921.
Year: 1922D Mintage 15,063,000 Numismatic Value Range: $14 - $400$8.6870102468 is the total melt value for the 1921-1935 silver Peace dollar on January 16, 2009.ref:http://www.coinflation.com/coins/1921-1935-Silver-Peace-Dollar-Value.html
Each Peace dollar contains 0.77344 troy ounces of silver and is valued at $17.26 when silver is at $22.36 per ounce.
The last Peace dollar was issued in 1935 so it can't be a 1942 Peace dollar. Look at the coin again and post new question.
No US silver peace dollars were struck in 1929 or 1930.
There's a Peace dollar but not a war dollar. Please see the Related Question.
All Peace dollars are 90% silver. The current silver value is $15.28. The collectible value depends on the the date, mintmark and condition of the coin.
If silver is at a spot price of $37.90 per oz a peace dollar would have a melt value of $29.32.
If the coin is a real Morgan or Peace dollar. The value is just for the silver, about $20.00.