Sennheiser HD 558 for $100 (limit 5)

The middle of the trio of the Sennheiser HD 5xx open-back over-ear series, the HD 558 is back on sale again, going for $100 with free shipping, with a limit of up to five per customer at Amazon by amazon actual where it averages 4.5 out of 5 based on nearly 600 customer reviews. Currently the HD 518 goes for $80, while the HD 598 with its unusual looks goes for $150. Many consider this series a good introductory open-back audiophile-on-a-budget type of a headphone option.