Aukey Bluetooth FM Transmitter, $15 with code AUKEYBC2
Aukey Bluetooth AUX Receiver, $15 with code AUKEYBC9

You don’t need a new car to stream Bluetooth audio from your phone, or even a new stereo: You just need one of these $15 gadgets from Aukey.

This one connects to your phone over Bluetooth, and outputs the audio over AUX.

If your car is so old that it doesn’t even have an AUX jack, this model transmits your Bluetooth connection over the FM station of your choice, creating a truly wireless (if not the best sounding) solution.