The "S" is a mint mark for San Francisco not a series identifier. But it still has a retail value of $3.80-$4.60 for coins with heavy to medium wear. $5.00-$9.20 for light wear.
Uncirculated coins start at $10.00.
1974 S (Proof) Quarter is worth $1.50.
1951 is a very common date for Washington quarters, if it has any wear, the value is for the silver only, about $3.50. If it has a "D" or "S" mintmark it may be worth a little more depending condition.
1/4 of a dollar
$3.00 just for the silver.
No "S" mintmarks on a 1961 quarter, only a "D". The coin is valued for the silver, about $5.00.
August 2, 2009 The 1968-S proof quarter has a value from $6 to $40 depending upon the actual condition of the coin.
the year is in the 1940's
With no mint mark next to Monticello, or a "D", it's worth about a dime. If there's a small "S", it's worth about a quarter.
Any of the circulated state quarters are worth 25 cents.
Depending on condition, it's worth $5-8.
The Canadian RCMP quarter is from around the 1960's it is worth 25 cents in bad condition and $1.25 in mint condition.
I assume you mean the date 1951 and not 1,951 quarters, LOL! Anyway, in circulated condition, most are worth about $3 for their silver content. A 1951-S in extremely fine condition would retail for a bit more, but that's all.