What this coin looks like (obverse, reverse, mint mark location, special features, etc.): A major variety of the 1804 Draped Bust Half Cent (Penny) features a combination of a plain "4" within the 1804 date on the obverse of the coin and no stems (stemless) on the wreath on the reverse of the coin as depicted above.
There are two major varieties on the obverse of the coin. One features a crosslet "4" and the other has a plain "4" within the 1804 date. The crosslet "4" has a small vertical bar crossing through the right-side end of the "4" while the plain "4" does not. The difference between the crosslet 4 vs plain 4 is depicted below in the example comparison image of the coins:
The other two varieties deal with the reverse of the coin. One variety has two stems extending from the wreath while the other variety has no stems (stemless). The difference between the stemless (no stems) vs with stems is depicted below in the example comparison image of the coins:
Coin value chart: Typical coin prices, values and worth in USD based on grade/condition