Okay, I'm stuck between buying a pair of Shure SE115's for around $80, and the Sennheiser CX500's that I've seen on Ebay brand new for roughly 20 USD. What should I do? I really want the Shures, but I'm actually saving for an iPhone, and the Shures will set me back a couple of weeks worth of saving. :/ So which one out of the two has the better sound. Also, which has more bang for the buck? Thanks in advance.