Without knowing what the OP means by affordable it's really hard to give suggestions. I've got multiple GrandStream cameras running on a ZoneMinder system. The cameras support 1920x1080, night vision with the IR LED's built-in, Power over Ethernet. I've used analog cameras plugged into a BlueCherry capture card. Resolution was low, night vision was OK (but not as good as the GrandStream), had to string the signal cable and power cable to the cams. Overall I like the new setup a lot more.
Grandstream does require DirectX to view the stream through their web interface but I've never used it. I only use the web interface to set resolution, frame rate and other setttings. All the motion detection is done in ZoneMinder. When I want to view what the camera is seeing I either use ZoneMinder or vlc directly to the RTSP feed.