Monoprice via Amazon offers Prime members the Enhanced Bass Hi-Fi Noise-Isolating Earphones, model no. 108320, for $4.59 with free shipping. (Non-members can spend $25 or more to qualify for free shipping; otherwise, shipping costs $5.74.) That's $3 under our September mention and the lowest total price we've seen for this model. (It's also $5 under Monoprice's direct price.) They feature a 20Hz to 20kHz frequency response, 14.2mm drivers, 48" cord, and more.