Walmart offers the Ematic Portable Bluetooth Wireless Speaker in Gray (pictured), Black, Red, or Blue, model no. ESB104, for $18. Choose free in-store pickup to dodge the $4.97 shipping fee. That's $2 below our May mention and the lowest price we could find by $6. This speaker streams audio from any Bluetooth-enabled device and includes a line-in cable, USB charging cable, and 15 hours of playback per charge.