Best Buy via eBay offers the Muse Brain-Sensing Headband in Black, model no. MU-01-BK-ML, for $179.99 with free shipping. (Amazon charges the same price.) That's $69 off list and the lowest total price we could find. It's designed to improve your meditation, and features seven sensors which detect and measure the activity of your brain. (When you're calm, it plays peaceful weather sounds, and when your mind wanders, the sounds intensify until you focus again.)