I have a 4-channel LaView system (you can get em at Memex, NCIX, Newegg, etc) for less than $200. You can get ones with 500gb HDD PVRs or without and add your own for higher storage.
http://www.newegg.ca/Product/Product...82E16881183006
-Free mobile app for remote viewing (as well as viewing recorded video)
-Great web interface and setup, very customizable.
-email notification if you want, on motion detect.