What book to buy next with this AP?

[Bumborro]

Just about to start running this and the (only?) books i have are the Ap, the corebook, Adv players guide, Bestiary I, Ultimate Magic (which we rarely use) and i think one of the players may have ultimate combat but Im not certain.

On a budget here, so I'd prefer to just get one more, which would you say I should pick up?

Thanks

[Adam Daigle]

I'd suggest Isles of the Shackles. It provides a ton of detail on the region and has monsters and events you could insert into the Skull and Shackles Adventure Path.

[Bumborro]

Awesome idea! And one I hadn't considered. Thanks, Adam.

[Adam Daigle]

Glad I could help. :)

[mogwen]

And you could add Pirates of the inner sea,new archetypes,new spells and lots of tips for playing pirates!