We think this is your coin, Joe. Hope so. It is a tong guk tong bo cash coin from King Sukjong of the Koryo Dynasty during the period 998-1097 AD.
These coins are not easy to find, especially in decent condition. Prices, in our view, are suppressed right now, as this specialized area of collecting has yet to take off in popularity. As the Internet introduces more and more people to the fascinating cash coins of the Sinosphere, prices will certainly rise. Also, as collectors uncover nice-looking, high-quality specimens, prices will skyrocket for those particular coins.
Here is our best guess at current value based on a few auction results we have seen around the Internet.
worn: $50 US dollars approximate catalog value
average circulated: $120
well preserved: $250
We consider the coin in our picture to be in average circulated condition. This particular coin sold for $91 at AnythingAnywhere in North Carolina during 2007. CoinQuest thanks Bob Reis of AnythingAnywhere for use of the coin image. Be sure to read our Important Terminology page for instructions about interpreting catalog values.
There is a great page introducing Korean coins like this at PrimalTrek [Click Here], one of our favorite sites for coins like these.