Definitely consider zoneminder. I've used it with Foscam and Crenova ip cameras with good results. The cameras I got were $30 for a basic dome and $70 for a pan

Definitely consider zoneminder. I've used it with Foscam and Crenova ip cameras with good results. The cameras I got were $30 for a basic dome and $70 for a pan-tilt. However, if you do decide to go this route I would be prepared to put all of the cameras on a separate network without access to the internet or the rest of the lan. They are literally little linux machines that shouldn't be trusted. Setup a firewall that ensure they can only connect to the zoneminder server.