I have a wifi setup on cameras for just the same reason.

I got several foscam and dlink cameras when they went on sale (and they do quite frequently).

I watched slickdeals and techbargains on my twitter feed to alert me on the deals.

Then I use blue iris for the managing of the alerts and storage of the movement the cameras detect. I get emails with still shots as well as a clip of the motion. I save the files to my home computer. (blueirissoftware.com)

My next house will have POE cameras, but until then these work great (all 25 of them)