Looking for an extremely cheap security monitoring solution

A question for experienced guys. I am looking for an extremely cheap solution for my backyard. I have weird neighbours and can’t trust them. Is there any modern and cheap solutions? I have WiFi all over my house area.

Security camera with motion detection?

maybe this, but it has to be as cheap as possble

All good options are not cheap. I don’t even know what to recommend… Try some mobile app surveillance if you have an old phone, it might help. Just google it.

What? For example?

Try Faceter of Alfred for example. Its enough to watch over some areas

There are some options for you,
No1, the cheapest one, the eWeLink camera app allows you to turn your old, idle Android phone to a security camera and monitoring via your eWeLink app, Echo show, Nest Hub, and eWeLink web.
No 2, any security IP camera, like SONOFF CAM slim, subscribe to a plan to unlock the additional features may needed.
No 3, the geek one, using any cam development kit to set up a monitoring system by yourself, like ESP32 Cam devkit and training your own AI algorith.

And what’s the difference eWeLink camera app from Faceter cameara of Alfred? Which one is better?

Land mines. Definitely land mines.

It’s really hard to recommend, for me, the answer is eWeLink camera APP definitely.

I use a waterproof outdoor camera eWeLink IOT Camera manufactured by Woolley, but supported on the eWeLink App. It includes motion sensor, microphone and speaker and integrates with other devices as well (e.g. link it to the device that opens the gate) The price is quite reasonable and they work well. Model GK-200BF6D.