Newegg offers the refurbished Creative D80 Wireless Bluetooth Speaker in Gray, model no. 51MF8130AA002, for $21.99 with free shipping. That's the lowest total price we could find by $2, although we saw it with a rebate for $6 less in July. (It's $12 less than the best price we could find for a new one.) Features include two 3" drivers, 3.5mm audio jack, toggling between two pre-paired devices, and AC power cord.
A 90-day warranty applies, but it's unclear who backs it.