BuyDig offers the Audio-Technica Professional Studio Monitor Headphones
, model no. ATH-M30x, for $49.99
with free shipping
. That's the lowest total price we could find by $19. (It was a buck less last month, although that deal required padding for free shipping.) They a feature 15Hz to 22kHz frequency response, 40mm drivers with neodymium magnets, 96 dB sensitivity, and collapsible design.