Supermarket chain Lidl had a promotion over a decade ago where they sold Air Berlin flights for 20€, the vouchers could be exchange for open seats in any flight

Supermarket chain Lidl had a promotion over a decade ago where they sold Air Berlin flights for 20€, the vouchers could be exchange for open seats in any flight for a year after the promotion was on. I bought dozens of them, and basically spent a whole year travelling for essentially nothing, and like the author in the story giving away air tickets on a whim.