Inexpensive solar panel monitoring

I bought the solar system at my home (Socal) from SunRun, where they provided an app and monitoring of panel performance. Shortly after they started charging a monthly fee for monitoring (the app is useless unless you pay) and now they transferred this service to Enphase who charges $999 for monitoring equipment and guessing a monthly fee as well. Does anyone know of an app or service that is cheaper (or free) to monitor panel performance?. I am on a fixed income.

Would love to hear your opinions on this subject. Thank you