The current second PWSE result for the title of this question is: lastminute.com.
The first is this question.
I’d try priceline and do it during the week, not on a weekend. http://www.priceline.com/promo/name_your_own_price/flights/
Credit:stackoverflow.com‘
4 Mar, 2024
5 Mar, 2024
5 Mar, 2024
4 Mar, 2024