Cheaper today, pricier tomorrow and a total bargain the day after. Online prices for products are notorious for fluctuating by the hour or even minute. These ever-changing e-commerce prices have their origins in bookings for air travel: In the 1980s, airlines in the US began to adjust prices based on data and using algorithms - the start of dynamic pricing. Economics historian Dr. Guillaume Yon researches this very topic: How airline experts once developed pricing systems and are still improving