There's a Peace dollar but not a war dollar. Please see the Related Question.
1 Dollar "Peace Dollar" 1921-1935 Commemorative: End of World War I Silver (.900) - 26.73 g - ø 38.1 mm so 90% is silver of the 26.73gm total weight
It's worth about a dollar just for the silver.
Average current market value for the 1991 PF Koren War Memorial silver dollar is $17.00-$23.00 depending on the actual grade of the coin.
The 1921 Peace dollar was minted to commemorate the end of World War I.
The coin is a very common date " War Years" Walking Liberty half, unless it's a super high grade coin the value is just for the silver, about $10.00
To clear things up, Morgan dollars were minted from 1878 to 1904 and in 1921, and the Peace Sign was created during the 1960s to protest the Vietnam War. What you have is simply called a Peace dollar; it honored the end of WWI. Please see the Related Question for more information.
1945 makes it a silver "war" nickel. It's currently worth a bit over one dollar for the silver content alone, and possibly more depending on condition.
The dollar
Not worth much. Face value or depending how much silver and grade of silver it was made of and from. Mexican money is pretty much worthless as is many other countries around the world. Russia, Canada, examples --Monies is worth only face value.
Most halves from the WWII era are common among collectors. Anything that shows evidence of wear will mostly be worth its silver value, around $7-8 as of 03/2010.
The biggest difference is Peace dollars exist and Liberty dollars don't. A very common mistake non-collectors or amateurs make with US silver dollars is they think because the word LIBERTY is on the obverse of a Peace dollar (or other coins) it's called a liberty dollar. No US coin is referred to as just a "Liberty" coin. Also this comes up with Morgan dollars, but with the national motto E PLURIBUS UNUM because it's on the front of the coin.
Up to 1964 you could get a silver dollar for itMoreSilver certificates were printed from the Civil War till the mid-1960s, although the last ones were dated 1957. Each dollar's worth of silver certificates in circulation had to be backed by an equal amount of silver on deposit with the Treasury. The price of silver was controlled by the government so it kept the currency's value stable but it also severely limited the government's ability to react to economic up- and down-turns. By the early 1960s industrial demand for silver had skyrocketed and many governments, not just in the US, were forced to deregulate its price. Because its value was no longer fixed the Treasury had to stop redeeming silver certificates for silver coins. Starting in 1963, low-denomination silver certificates were phased out and replaced with the same Federal Reserve Notes that were issued for other, higher denominations.