Items like liquor, cigarettes, perfume, jewellry, and cosmetics are heavily taxed (luxury tax) because they are non-essental items. For example, a bottle of Kahlua here is about $22.00. I get it in Mexico for about $10.00 a bottle. You don't pay U.S. taxes because you are not purchasing the item in the U.S. (which is also why the duty-free shops onboard don't open until the ship is in International waters).