How do I monitor home security without expensive subscriptions?

[Oust1999]

I just moved into a small rental and want basic security monitoring through my phone. I have an old Android tablet and a few WiFi cameras, but most apps seem to require monthly fees. Are there reliable software options that work locally or with minimal cloud costs? I don't need professional monitoring, just alerts when I'm at work.

 

[Arence40]

I use Alfred on an old phone as a motion detector. It sends clips to my email for free. The delay is about 10 seconds, but for checking if my cat knocked something over, it's fine. No subscriptions, just ads I barely notice.