I am looking to get into the game. Now that there are 3 force packs do I need a second core set or should I get 1 core and all the packs

Second core before anything else, especially if you want to run Jedi and/or Sith decks.

The first force pack "The Desolation of Hoth" is really quite useful as there are several objectives that are worth while, but a 2nd core set is still top of the list.

The only reason I can think for someone to not buy two core sets is if money is really an issue for them (and who can blame them?). If that is your concern, you might try buying one core and the current Force packs and see how you go. I'm betting, however, that once you start building your own decks, you'll be wishing you had two copies of Vader, Palpatine, Luke, Yoda, Han, Home One, Tarkin, Devastator, and others.

Buying two core sets seems to really turn people off, but it's a really good deal compared to traditional CCGs and even compared to other LCGs! The vast majority of cards from your second set are completely useable. Also, you can still be decently competitive with just two core sets even though a few Force packs have been released.

If you really like this game, you'll be buying a second core set, but I suppose there is no harm in starting with just one.