World Wide Stereo via eBay offers the Klipsch Reference S4 Premium In-Ear Noise-Isolating Headphones, model no. 1013730, for $49.99 with free shipping. That's the lowest total price we could find by $7, although they were $4 less two weeks ago. Features include four different-sized ear tips, storage case, clothing clip, 10Hz to 19kHz frequency response, and more.