@Tinkeringbell I'd suggest searching wireless battery wifi video camera
. Maybe solar
instead of battery
if you're interested in that route. The problem you're likely going to find is that, at that price point, unless you buy a name brand IoT-style subscription security camera, you're probably not going to be able to stream the content; rather, you'll probably have to connect to the camera's built-in "web server" / wifi router, as an isolated server-client network of 2, no internet connection.