Mpow Bluetooth Audio Receiver, $13 with code J9E2LO9V

Chances are, you have some old speaker systems lying around that were created before the widespread adoption of Bluetooth. But you can still add wireless streaming to any of them for just $13 with this dongle from Mpow. We’ve seen a lot of similar products before, but this one comes with both a 3.5mm connection and RCA cables, so it should work with just about any audio system.