Collectible coins in the United States include a variety of denominations, with notable examples being the 1-cent (penny) and 50-cent (half dollar) coins. Proof sets from years like 1999 feature coins that are struck with a higher quality finish, known for their mirrored surfaces and sharp details, making them highly desirable among collectors. These sets typically include various denominations, showcasing iconic designs and limited mintage that contribute to their collectible value.

Item Denomination Series Year Mint
1999-S 1c-50c Proof Set 9 Coins 1c-50c Proof Sets 1999 San Francisco