Real Duty Free has disappeared in Europe. Many items sold in the so-called "Duty Free: shops are more expensive than in cities.

Israel still does have duty free, but the only major bargains are on cigarettes, alchohol, and perfume/make up.

I can buy a carton of Israeli cigarettes for $12 or American for $18. Keep in mind, however, that it is illegal to bring more than one carton of American-made tax-free smokes into the States. I don't know how much you would really be saving for your friend.