Sony HWSBTA2W compare (Bluetooth wireless audio transmitter)

The Belkin Bluetooth Music Receiver is a cheap and easy way to add wireless audio streaming to any powered speaker system or audio component with a spare input.

If you're looking for a relatively cheap way to add Bluetooth wireless audio streaming to a powered speaker or audio component with an audio input, the Logitech Wireless Speaker Adapter is a good solution.

For cars with an auxiliary input but no native Bluetooth, the GoGroove SmartMini Aux is an effective means of adding both hands-free call capability and audio streaming from a smartphone.