As one of its daily deals, 1Sale offers the Zooka Bluetooth Wireless Speaker for iPad in Black (pictured), Red, or Navy, model no. ZUS-2, for $24.99 with free shipping. That's $50 under our mention from February of last year and the lowest total price we could find by $15. It's compatible with most Bluetooth devices (in addition to the iPad), has a range of up to 30 feet, and features up to eight hours of play time. Deal ends today.
There's a less expensive way, and then there's the way that works for you. The two may not be the same.