There are several types of metal detector hobbyist activities:
Coin Shooting: These are people who look for modern as well as old coins. Popular "digging" areas include parks, recreation centers, playgrounds and lakefronts.
Prospecting is looking for valuable metals like gold and silver in their natural forms, such as nuggets or flakes.
Beach Combing: This is where people scour the beach hunting for lost coins or jewelry. Beach hunting can be as simple as pointing and walking. Often hobbyist find treasures within a few hours.
Metal Detectors are found on many websites including ebay: