Hi Andrea,
I just submitted new code that should implement API support for the Nest Cam in the Nest binding. If you do decide to get a Nest Cam, please try this code and let me know if it works as intended. I won’t merge it into openHAB until I’m certain that it works!
I don’t have personal knowledge of Nest Aware, what it offers or what it costs, just saw the mention in the Camera Guide.