I ordered one of these for a rear view camera and have been quite happy with it.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
My rig came with side view cameras but I rarely use them.
I learned a long time ago how to use mirrors, so the side view cameras, while 'cool' are effective I just don't think to use them.
It might be different if they were on all the time, but they are only one when the corresponding turn signal is on. If I'm changing lanes I've already verified using the mirrors that there is a place for me to go before I turn on the turn signal, so at that point the side camera is useless.
When sitting waiting to make a turn, like at a traffic light, having the side camera take over the view from the rear is often annoying because I can't see what's directly behind me (and I already know there is a curb and pole beside me
).
If you go for a wireless rear view camera be sure and get one with a digital signal, similar to what I linked to. I discovered on my previous rig that going cheap with an analog camera gets you a signal that drops our or with lots of static when going down the highway. Apparently you can actually outrun the signal from the camera so that it never quit makes it to the monitor - at least not consistently. Makes for an annoying time trying to see what's behind you when you keep leaving the signal behind.