TomTop offers this Multifunctional Wireless Car Charger for $10.89. Coupon code "AK5812" drops it to $6.89. With free shipping, that's $7 off and the lowest price we could find. It features an FM transmitter, Bluetooth, and microSD card player.

Note: The countdown timer on the product page does not reflect an actual expiration time and resets daily. This item ships from China and may take two to six weeks to arrive.