"Whats a round about value for a coin like this?"
As Don sad, it is really hard to say, but once it is identified, published, and in the best case scenerio, gets some attribution, the value goes up appreciably. What you've found ("I K") is an unlisted counterstamp referred to as a "maverick". Here's a similar type of two letter maverick I dug several years ago which was then unique (like your's) and which "United States Tokens" listed for value $80.00. Since then a few others have been found in the same area of the country, and once they are reported it will be easier to attribute the maker (and again, once attributed, the value goes up considerably on all of them)
Once again, I think you should write to Russell Rulau, the author of "United States Tokens", and report your find. He has the largest data base, and as well, he is working on a cd addition to the book. You can contact him through Krause publications, 700 E. State St. iola WI 54990-0001.