What this coin looks like (obverse, reverse, mint mark location, special features, etc.): One major variety is the 1837 Coronet Head Large Cent (Penny) featuring the smaller letters on the reverse and the "Head of 1837" with plain cords in lady liberty's hair on the obverse of the coin as depicted above.
The difference between the small letters vs medium letters on the reverse of the coin is depicted in the example comparison image below. Note the size of the letters and the spacing between them:
In addition: Another difference deals with the portrait of liberty on the obverse of the coin. The "Head of 1837" liberty features plain cords in the hair whereas the "Head of 1838" features beaded cords. The differences are depicted below in the example comparison image:
Coin value chart: Typical coin prices, values and worth in USD based on grade/condition