Pennies have always been reputed to bring good luck. Finding a penny (or indeed any coin or other form of money) is said to endow one with good fortune, particularly if discovered "heads up," and is suitable to be carried as a charm. If the discovered penny was minted in the year of one's birth, it is supposed to be especially lucky.
A penny may be tossed overboard when one sets out to sea, in hopes of appeasing the marine gods and thus ensuring a safe passage. Similarly a penny (or other coin) may be tossed into a well or pool in the belief that so doing will cause one's wish to be granted.
Displayed here are a giant "Lucky Penny" together with (clockwise) an Indian-head penny embedded in a good luck token (from the Pan-American Exposition at Buffalo, NY, 1901), a "Lucky Penny in the Bottle," a "Lucky Wooden Nickel," a "Good Luck Souvenir" token (from Florida's Sunken Gardens), a vending-machine-flattened-and-embossed "My Lucky Penny," and a common penny (found on a sidewalk).