25 cents unless it's uncirculated. In that case values as of 05/2010 range from about 50¢ for the lowest-quality uncirculated coin to about $400 for an absolute top-grade coin, with an average of around $3-5 for most.
1966 quarters are anything but rare. Nearly a billion quarters were minted in 1966 as the Mint churned out oceans of the then-new clad coins to replace 1964 and earlier silver coins. Even today they continue to show up in change, though less frequently than before.
Note that US Coins dated 1965, 1966, or 1967 don't have mint marks.
The coin is face value.
No U.S. coins dated 1966 have a mint mark. The '66 quarter is worth 25 cents.
If you mean a 1966 American quarter, then none.
The value is currently around 4 cents.
10 cents.
The coin is face value.
There were no S-mint quarters struck from 1955 to 1967 inclusive and no US coins carried mint marks during the transition from silver to clad coinage in 1965-67.
25 cents.
In circulated condition, it has no added value. A nice uncirculated one is worth a dollar or two.
A US quarter has a face value of 25 cents.
No U.S. coins dated 1966 have a mint mark. The '66 quarter is worth 25 cents.
A 1765 US quarter does not exist.
On eBay they're sold for $2.
The first US quarter was struck in 1796.
25 cents. It contains no silver and is only face value. Millions are still in circulation.
No US quarters were struck in 1922. The US did not make ANY quarters dated 1922.
The coin is a 2001 Vermont State Quarter, it's 25 cents.