Amazon offers the Sennheiser HD 600 Over-Ear Headphones in Black, bundled with a $150 Amazon Gift Card, for $399.95 with free shipping. Assuming you'll use the gift card, that's tied with our mention from last month and the lowest total price we could find by $107. (Most stores charge $400 without a gift card included.) These open-back circumaural headphones feature a 12Hz to 39kHz frequency response, 300-ohm impedance, Kevlar-reinforced detachable 10-foot cable, and aluminum voice coils.