I have the core set and recently bought the saga expansion "The Hobbit: Over Hill and Under Hill." I was attempting to build the decks as described in the back of the expansion rules and it says to use "Burglar Baggins" x3 for both decks. I only have 3 of the "Burglar Baggins" cards. Am I missing cards or is there a typo or something else missing?

you're not missing anything. i think they just assume since they are giving two deck lists for presumputally two players that both players have the expansion and would have 3 copies. the listed deck lists are kind of iffy anyway so dont feel like you have to be forced into making them exactly the same

Kind of what I figured. I don't play with other players in my area since I haven't been able to find other players in my area. I play with my family since I have a large family but only buy one game. Thanks for the reply.