Sony's new MDR-XB50BS Extra Bass Sports Wireless in-ear headphone is worth considering for a few reasons: Not only is it relatively inexpensive at around $60 online (£60 or AU$130), but just as importantly it fits well and sounds good, particularly if you listen to bass-heavy music.
It's got some small downsides, but the reasonably priced Sony MDR-XB50BS is a step up in sound from a lot of inexpensive wireless sports headphones.
The Sony MDR-XB50BS is affordably priced, sweat-resistant, sounds decent and fits well (it's easy to get a tight seal); Battery life is good at 8.5 hours and the headphone has strong bass performance.
Not the greatest-looking wireless sports headphone; performed only OK as a headset; no protective case.