According to Time, one of the most valuable pennies is the 1943 copper alloy penny. This penny was created accidentally and only 40 of them are said to exist. As of 2014, one of these 1943 pennies sold for approximately $1.7 million dollars.
Another rare and valuable penny is the 1969-S Lincoln penny, where most features on the obverse is doubled. If all of the features on the obverse is doubled then the penny isn't valuable. However, if the 1969-S Lincoln penny has everything doubled except for the mint mark, then the penny could be sold for up to $35,000.