I added a small backup camera to the video input on the G3X. It allows me to have a view in front while taxiing, but is primarily for off airport use. It makes it much easier to see large obstacles while taxiing in the rocks and weeds.
The total cost of the camera (https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1) and RCA to BNC connector (https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1) was only $45 dollars on Amazon.
I used the transponder c/b, so the camera is only powered when the avionics switch is on. The right side cockpit panel was removed, which allowed easy access for the wire run from the firewall to the G3X and circuit breaker. Total time was approximately 1.5 hours.