Walmart offers the Dual Electronics Single-DIN In-Dash Receiver with Bluetooth for $9.99. Opt for in-store pickup to dodge the $5.99 shipping charge. That's the lowest price we've seen for any in-dash receiver. (It's the best deal for this model today by $17.) It features USB and aux inputs and a remote control.
With these companies, it might be easier than you think to negotiate your monthly bill down.