AVOID wifi cameras, theyre more trouble than running a cable will ever be
have a look on amazon for swann 1080 PIR camera systems, DVR, 1tb HDD, 4x cameras with night vision, all for around £250
their new 4k enforcer cameras are shit, no night vision, they have a white LED to illuminate things in the night, and flashing red and blue LEDs to scare the bad guys away, every one of those systems ive installed has had an issue with at least 1 camera within the first few weeks
EVERY wireless camera system ive ever installed has ended up being replaced with a wired system, wifi cameras still need a constant wired power connection, so you still need to run a cable to them
very simple app to setup and use
(ive been installing swann stuff for over a decade, as well as other stuff, but swann is the most user friendly and best price for what you get)
Hikvision is also a great make, but costs more, and the app isnt as user friendly