THEM: i would like the book and two hats.  YOU: i would like that exact same thing.  THEM: how about i get the book and two basketballs then and you can have the hats and a basketball?  YOU: no. i'll need the book for sure. everything else is negotiable.  THEM: if you get the book, i will need everything else.  YOU: fine. i don't love that, but fine.  THEM: great.