Panasonic RPTCM125K Headphones https://www.amazon.com/dp/B00E4LGVUO/ref=cm_sw_r_awd_dMCgub0GH8VGN
These won some huge comparison of sub $50ish ear buds in some audiophile article I read a while back. I couldn't find it again, sorry. But even without the article to back it up, I can't say enough nice things about them, from my own experience. They're more comfortable than any ear buds I've ever used. They're better sounding than any other ear buds I've ever used. And they're $15.
Can't beat that.
Honestly, without super super high bitrate audio, I really can't tell much of a difference between these and a pair of Bang & Olufsen headphones I have... IMO, nothing you pump out through your phone could take advantage of any better headphones anyway.
Edit: Found the article if you're interested. http://m.thewirecutter.com/reviews/best-headphones-under-30/ I guess it was $30, not $50.