We are only renting but living in an area with a high incident of break and enters. Nothing of great value to steal in the premises but still prefer a low cost preventative measure. Don't need CCTV cameras, or anything too elaborate or complicated to set up, only the basics.
Keep in mind we are only renting so unable to make any modifications in the premises or alter any of the fixtures e.g. can use scotch tape to mount things but no screws or nails.
It's only a small sized two bedroom unit.
I've seen this kit on ebay which seems like a good deal for $80 as it includes the proximity sensors, control module, door/window sensors, and remotes, etc.
http://www.ebay.com.au/itm/Wireless-PIR-Motion-Sensor-Home-H…
Some other products of interest:
http://www.ebay.com.au/itm/2016-WiFi-GSM-GPRS-Home-Burglar-A…
You might also be interested in Xiaomi's smart home kit
http://www.gearbest.com/smart-home/pp_197862.html
It uses a central hub, plus a PIR sensor and a two-part proxy sensor that alerts when a door or window is opened.
I've yet to see any 'proper' reviews though. Just a lot of unboxings on Youtube but there are hardly good review vids.