Collectible coins encompass a variety of forms, including official currency, commemorative issues, and medals. In the United States, one-dollar coins have been produced in various designs, including the Sacagawea and Presidential series, which often hold numismatic value beyond their face value. Modern medals, not to be confused with coins, are typically struck to commemorate events, people, or milestones and may feature intricate designs and limited mintage, appealing to collectors for their historical significance and artistic merit. The market for these items fluctuates based on rarity, demand, and condition, making them popular among numismatists.