Buy your airfare on the weekends. A study by the Airline Reporting Corporation looked at 26 million fare transactions and found that the lowest ticket prices. rental so if the cost drops, they rebo. Apr 20, 2012. Avoid vacation timeā€”on domestic flights, that means June 15 to September 6 and. For late-breaking deals, check out lastminute.com. So if you're serious, sign up to get price drop alerts from as many…