This Planet Money episode, a co-hosted podcast, explores the history and economics of duty-free shops. The podcast begins with an anecdote about the world's first duty-free shop at Shannon Airport in Ireland, then delves into its origins, tracing how a bartender-turned-entrepreneur, Brendan O'Regan, exploited a loophole in maritime law to convince the Irish government to allow tax-free sales to airline passengers. The hosts discuss the subsequent boom of the duty-free industry, its global expansion, and the marketing strategies employed by companies like Toblerone. Finally, they analyze whether duty-free shopping truly offers significant savings for consumers, concluding that while some items (like cigarettes) are considerably cheaper, others are not necessarily better deals than those found outside airports. For example, the hosts found that while cigarettes were significantly cheaper in duty-free, the price of Toblerone bars was almost double the US price.