Geocoins are found in Geocaches, bought or traded. In recent years they have become very much a collectable with the most sought after Geocoins going for a much as a couple of thousand dollars!
They are usually stamped with a code that can be entered into a Geocache Listings site. This way the Geocoin can be tracked as it travels from Geocache to Geocache.
In recent years, the Geocoin craze has taken off dramatically, and there are hundreds, if not thousands of different ones out there today. Due to the fact that many of them have unique icons, many people bring such Geocoins to Geocaching events so that others may see the coins and then collect the icons as part of their stats.
Keep on cachin’!