A single Security Monitor Pro 4 camera license will monitor and record from all 4 of your cameras simultaneously. You will need the 4 IP cameras, 1 PC to run Security Monitor Pro, and an internet connection. If the camera does not have settings to invert the image, Security Monitor Pro can invert it. Axis, Trendnet, D-Link, and Linksys all make good cameras that will be suitable for your needs. We have an article on selecting a security camera. You may find this article helpful: https://www.deskshare.com/resources/articles/wcm_SecurityCamera.aspx