What this coin looks like (obverse, reverse, mint mark location, special features, etc.): This is one of the rare and valuable 1972 Doubled Die Obverse DDO varieties of the Lincoln Memorial Cent. This Philadelphia-minted coin is best identified by the prominent doubling of the letters "In God We Trust" along the top of the coin and the doubling of the word "Liberty" on the left side. In addition: The 1972 date is also doubled on this penny as well as depicted in the example image above. Source of example image is courtesy of Heritage Auctions.
Coin valuation chart: Typical coin prices, values and worth per grade or condition - in USD