For under $40, you can have a life-sized cardboard likeness of a law enforcer in your home. Very simplistic, but I hear it does the trick. At first glance, these cutouts appear to be real policemen, and can be instrumental in preventing burglary, vehicle speeding in residential areas, and overall security.
Add this to the fact that if purchased, not many people will have the same security device.
It may not offer the same benefits as an alarm or video surveillance system, but it can surely act as a makeshift substitute.