actual cams
https://www.gearbest.com/surveillance-camera-system/pp_1232234.html?wid=37
I believe would be sufficient
something like
https://www.gearbest.com/surveillance-camera-system/pp_1064299.html?wid=21
or
https://www.gearbest.com/surveillance-camera-system/pp_637433.html
(+HDD)
seem to be almost sufficient, considering cost (cheapness) but being Wi-Fi only...
even
https://www.gearbest.com/ip-cameras/pp_315355.html
(just add HDD and ever so many meters of cabling) would be OK, just shame with ever so little info on actual performance, features and set up, as all there available as "reviews" are of "Chinese way of marketing", not that I could rely on...
So, "all in all it all boils down to"... weather to get 4 ch DVR CCTV or even 8cam DVR CCTV or to go perhaps with one 4 cam DVR set up and second (internal) 4ch IP NVR CCTV...
Critical issue here is opposite to the logic, as less important, but needed to be more feature rich (as Movement detection+ auto record in to local storage + IE app alerts and perhaps stream in to app paired device) would end up being Wi-Fi ones as "base set up"
Whilst "One's for the show"- external need to be clear "proper" wired ones connected to DVR box.
Perhaps 2 (+ x4 of each (used in total 5 or 6 of them) Cams) of cheaper DVR and NVR is the solution.