2015 Prius C One cruise control and Backup Camera

If I have it right, you just need to get the control stalk. The Rostra aftermarket kit is (last I checked) a box containing an OEM Toyota stalk and some incorrect instructions.

n.b. I put a Rostra kit on our old Hyundai. Works great but the instructions were poorly done and I had to do some detective work to properly finish the job.

Toyota doesn't provide instructions at all; they think they are selling you a replacement stalk for your ≥Two. You ought to be able to rent the manual and apply the procedure for a broken stalk.

I've never seen a comparison of price between the two sources.

I don't think the wiring is there. I have no idea if the head unit they used that year even has a video input. Information is hard to come by on these just because nobody makes money on old Toyota head units, so nobody bothers to study or remember the details.

One gotcha I can share: The native Toyota cameras run on 6 volts. Toyota head units provide the necessary 12v->6v adaptation. Almost all aftermarket cameras are 12v. The Toyota head units accept a completely standard composite analog video signal, nothing odd about that- you just have to get the power supply correct. I imagine you could just wire in a $1 relay to trigger +12v on the camera line from 6v detected out of the head unit.