Collectible coins, particularly those from the United States, encompass a variety of types including historical coins, commemorative issues, and error coins. Copper coins, such as those produced by Machins Mills, are notable for their role in American numismatic history. The Machins Mills coins, minted in the late 18th century, often featured designs that were imitations of official currency and are sought after by collectors for their rarity and historical significance. Notably, coins from 1776, including those associated with the American Revolution, hold particular value due to their age and connection to foundational events in U.S. history.