eXpansys offers the Hype Portable Mini Bluetooth Speaker in Black, model no. HY-525-BT, for $22.99 with free shipping. That's the lowest total price we could find by $7, outside the price below. It features Bluetooth connectivity, 3.5mm line-in, integrated rechargeable battery, music pause when the phone rings, and more.

A close price, Geeks.com has it Black or White for $19.99 plus $3.30 for shipping.