MiniInTheBox offers the Xiaomi Noise-Cancelling In-Ear Headphones in several colors (Silver pictured) for $3.99 with free shipping. That's $6 off and the lowest price we could find. They feature an in-line microphone.
Note: Uncheck "Add Shipping Insurance to your order" during checkout to remove the 99-cent fee.
Update: It now includes a 50 cent small order fee.