Amazon has several deals on the Guardline Wireless Driveway Alarm.
Guardline Wireless Driveway Alarm – $69.99
Guardline ¼ Mile Long Range Wireless Driveway Alarm – $99.99
Guardline Wireless Driveway Alarm w/Four Sensors Kit – $178.99
1/4 Mile Long Range Wireless Driveway Alarm w/Two Sensors Kit – $164.49