I had both bullet and dome PoE Chinese cameras from Amazon with a separate power injector. They were connected to a Synology NAS for storing the video using the Synology surveillance software. Choose the camera type based on the location/application, dome cameras are slightly more tamper resistant.
PoE nice because you only need to run a single cable to each camera. Having used a system like that for a few years but I wouldn't use that system again. I would buy an all in one system with a DVR and the cameras, like something from Lorex.