Alien Shop via Amazon offers the Sound Intone In-Ear Sport Headphones in several colors for $12.20. Coupon code "JUZC7M5P" drops it to $5.49. Plus, Prime members bag free shipping. That's $20 off list and the lowest price we could find. They feature an inline microphone, a frequency response of 18Hz to 20kHz, and are compatible with Android or iOS devices.