What this coin looks like (obverse, reverse, mint mark location, special features, etc.):
One major variety is the 1814/3 Capped Bust Half Dollar overdate error. This variety features an 1814 date struck over an 1813 date which resulted in parts of the "3" being seen within and around the overlying "4". These features are easy to identify and 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