Walmart offers the Blaupunkt Toronto In-Dash AM/FM Bluetooth Media Receiver for $8.50. Choose in-store pickup to dodge the $5.99 shipping fee. That's $8 off list and the best deal we've seen for any in-dash Bluetooth receiver. It features an LCD display, AUX and USB inputs, and a micro SD card slot.
Before you spend another dollar on items and services like these, check with your public library. You will likely be surprised by what it offers for free.