I use an old cell phone with a dash mount and DailyRoads app.
Ooooh, that looks promising. We have a third car without a camera but do have extra old phones around. Do you have yours hard wired to always provide power to the phone to keep it alive when not using it, turn it on/off manually, or just let the phone battery drain down when not in use? I see the app has the ability to auto-start on boot, so that is a nice feature.