Monoprice offers its Monoprice Over-Ear Noise-Canceling Headphones for $74.99. Coupon code "SD25" drops that to $49.99. With free shipping, that's $13 under our February mention and the lowest total price we could find now by $45. They feature a 20Hz to 20kHz frequency response, 92% linear reduction in noise pressure, 35dB passive sound isolation, and a 3.5mm to 1/4" plug adapter. Deal ends September 17.