What this coin looks like (obverse, reverse, mint mark location, special features, etc.): There is a major variety of the 1888 Indian head Cent (Penny) where the 1888 date was punched over a 1887 date. This resulted in an 1888/7 or 8/7 variety where a small subtle portion of the "7" appeared under the leading "8". One way to identify this error is to note a small knob under the "8" which represents the bottom of the "7" as depicted in the example image of this penny above. In other cases an additional small portion of the underlying "7" may also appear above the last "8" in the 1888 date as well.
Coin valuation chart: Typical coin prices, values and worth per grade or condition - in USD