Happy Tao via Amazon offers the Lumsing 2-in-1 HiFi Bluetooth Transmitter / Receiver for $27.99. Coupon code "DUXOTF2E" drops it to $21.99. With free shipping, that's $8 off list and the lowest price we could find, although we saw it for a buck less in December. It can transmit or receive a Bluetooth audio signal (adding that functionality to speakers, headphones, etc.) and supports aptX and aptX-LL audio codecs.