I had this other idea that if you want to get somewhere(B) and you don't mind visiting other places if the flights are really cheap, you can get from A to B spending couple of days in C and maybe even in D so that A -> C -> D -> B. It is easy to pair these flights in Europe, so that every flight will be <2hours and will cost 10-25$. I think I even started coding this, but ended up having not enough time, and brute-forcing this problem is sort of hard. Maybe there already is a ready app for that.