First of all thank you for your responses
40$ for the mic and 50$ for the headphones is not really balanced for me.I will use the mic for only occasional skype calls.Which is maybe once a day.So i would like to spend the most of the money for the sound quality.Sennheiser hd518 seems good but i heard it has way worse sound quality than 558's.But i will buy them if their price just drops to 50$ or so.Still would like to get your opinion about 558's cause i kinda lean towards them.