1) Go to a store with a friend, and ask him to grab randomly 3 headphone sets, while you're hitting on the hot girl that works at the store.
2) Ask him to grab the cheapest possible, another middle priced and another at around 150€.
3) Try them, with the help of your friend, without you knowing which one it is.
4) Realize how you can't barely ear/feel any difference between models, thus you should go with the cheaper headphones, realizing overpriced headphones just carry that pricetag because they are a fashion items made mainstream by famous people who are paid to wear them, making the public act like a sheep herd.
5) Live a better life in peace with cheap headphones that perform just as good as those one with a "B".
NOTE:
Of course, if you're a musical guy, and sensitive to minor sound fluctuations to the point you can actually distinguish the sound quality and have the input equipment (not any smartphone or your random average laptop) to bring out the best of those pricey headphones, then go for it.