What this coin looks like (obverse, reverse, mint mark location, special features, etc.):
One major variety of the 1974 D Kennedy Half Dollar features a doubled die obverse (DDO) error. The doubling is more prominent on the right side of the coin in the words "WE TRUST" in the motto "IN GOD WE TRUST". The upper-right tip of the letter "T" in "LIBERTY" also has noticeable doubling as does the right tip of the "4" in the 1974 date. These doubled die features are depicted by the arrows in the example image above.
Coin valuation chart: Typical coin prices, values and worth per grade or condition - in USD