Monoprice offers its Monoprice Premium Hi-Fi DJ Style Over-the-Ear Pro Headphones in Black, model no. 8323, for $19.99. Better yet, add two to your cart and redeen coupon code "AFF5" to drop the price to $34.98. With free shipping, that's $17.49 per pair and the lowest total per unit price we've seen. (It's also a current low for two by $21.) They feature a 3.5mm jack, two 3.5mm audio cables, and 3.5mm to 1/4" gold-plated adapter plug. Deal ends June 7.