A U.S. penny forged in 1792 is up for auction at Stacks Bowers in Baltimore, with an estimated value of $2 million...Also offered for sale in the same auction are a silver center cent -
Named the “Birch Cent” after its designer, the coin is one of the first pieces of U.S. currency ever minted, and it's one of just seven of this particular design that remain...
It was considered a collector’s item as early as 1882, when it was offered as part of the collection of Charles I. Bushnell Esq., a collector of Americana. It popped up eight years later, in 1890, and again in 1921. Four years after that, in 1925, it was advertised for sale for $1,000 (approximately $13,500 today, adjusted for inflation).
and a Confederate half-dollar -
While writing the title I wondered about the etymology of the term "pretty penny" as an indication of amount rather than beauty. It's not explained at Word Wizard; the Online Etymology Dictionary traces that usage to the 15th century and compares it to the modern phrase "pretty please as an emphatic plea."