This Logitech unit will connect to your phone via Bluetooth and your stereo with a cable. Sold by Newegg (Amazon has it a little cheaper).
http://www.newegg.com/Product/Product.aspx?Item=N82E16875873003&ignorebbr=1&cm_re=bluetooth_audio_receiver_rca-_-75-873-003-_-Product
This Etekcity unit will do it, although I've never heard of the brand for $20 it's worth a try.
https://www.amazon.com/Etekcity-Wireless-Bluetooth-Receiver-NFC-Enabled/dp/B00KXYXXK2