It's not easy to add smartphone-based infotainment to your existing car, especially if you prefer Android Auto. Many aftermarket head units are either devoted solely to Apple CarPlay (like Pioneer's AppRadio 4) or mind-numbingly expensive (such as the $1,400 AVIC-8200NEX). Sony is aiming to fix that. It just unveiled the XAV-AX100, a receiver that offers both Android Auto and CarPlay for a reasonable $500 -- even the relatively frugal AppRadio 4 costs $600.
This isn't the most elaborate receiver (it handles 55W x 4 channels and produces virtual sound stages). However, it does have its own device-independent interface with Bluetooth and USB audio, as well as rear camera support. The biggest obstacle may simply be the wait. You won't see the AX100 until late November, so it won't help you navigate your end-of-summer vacation.