Aukey Direct via Amazon offers the Aukey FM Transmitter Radio Car Kit, model no. BT-C4, for $15.99. Coupon code "VQIE5FRX" drops it to $6.88. Plus, Prime members bag free shipping. (Non-members can spend $49 to bag free shipping; otherwise, it adds $5.99.) That's tied with our September mention and the lowest total price we could find for such a kit by $8. It features a cigarette lighter power supply, 3.5mm jack, USB charger port, and digital station readout.