I agree wit sel_69l, the coin is about AU to UNC. It is fairly common, with 60 million being minted in AH1354. Anyway, you did great buying it for under $10, that means you only paid melt value for it (maybe even a little below). I would estimate its value at about $20, but if it grades UNC, then you are looking at $25-$30.
It really is a beautiful coin, I have one dated 1370.