Yet money talks/and the wiset/have sometimes been known to count a /few coins too many. Who does Creon say this to, and what kind of literary device is this?
As you mention, Creon is speaking these words. In this context, Creon is addressing a priest. A bit later on a guard comes into the scene. The discussion is about keeping and obeying the laws of the land. In this case, Creon has forbid the burial of Polynices. The priest responds by saying that no one will break the law, because no one wants to die.
Creon, then, states that sometimes people will even dare to break the law, because they love money. There is a power that money possess, which controls people, even the wisest of people.
The literary device in view is personification. More specifically this means to give human like qualities to inanimate objects. In this case, money is personified. Money speaks.