How much is a 3 dollar coin worth?

This unusual denomination was struck for 35 years at 4 different mints, so more information is needed to identify it. If you can determine its condition and what mint mark, if any, it has you can look at the site below under Related Links. Otherwise please post a new question with more specific details including its date, how worn it is, and if the coin is dated 1860 or earlier, whether it has a mint mark on the back - there may be a small S, D, or O.