JBL offers the refurbished JBL Under Armour Sport Wireless Bluetooth In-Ear Headphones in Black for $29.99 with free 2-day shipping. That's tied with our mention from a week ago as the lowest price we've seen. (It's the best deal now for a refurb by $30 and $130 under the best price we could find for them new.) They're sweat-proof and feature an inline 3-button mic, 8-hour battery, and 10Hz to 22kHz frequency response.
Note: A 1-year JBL warranty applies.