What this coin looks like (obverse, reverse, mint mark location, special features, etc.):
One major variety is the 1811/0 Classic Head Large Cent (Penny) overdate error. This variety depicts an 1811 date struck over an 1810 date. This resulted in the underlying "0" appearing under the last "1" digit in the date. This can be clearly identified by noticing most of the underlying "0" showing up around the "1". In some cases other numbers are doubled as the date is struck over another date. The differences between the normal date vs the 1811/0 overdate can be seen in the example comparison image above.
Coin valuation chart: Typical coin prices, values and worth per grade or condition - in USD