THEM: i would like the hats and the book.  YOU: how about you get all the hats, i get book and ball?  THEM: is that your absolute best offer?  YOU: best i can do ; i definitely can't part with the hat.  THEM: i thought you wanted the book and ball?  YOU: i did... i meant the book, sorry!  THEM: okay! i'll take all four hats. you take the rest.