Lo Kingdom is ripping you off at the end when he spots the coin and pays you extra for it. You could actually get more for it if you kept it to sell to someone more reputable... or, you know, the point could also be yours if you decide to hang it on the wall of your house, it's up to you. However, there's no way you're going back in those woods to collect anything after the job is done. How do you make sure you get to keep the coin at the end of the game?
Let me know if you need a further hint :)