ADT Security Services Inc

I just bought a house built by Mercedes in Crystal Falls.  It is pre-wired with a security system (all contacts at windows/doors) but I needed to get the control panel hooked up and keypads installed.  I called ADT and they gave me this offer:
"Get a FREE Security System (an $850 value), with an ADT Money-Back Service Guarantee With our promotion, you will receive the following for FREE:
·         $850 Value of Free Security Equipment
·         Wireless Master Control Panel Keypad, with Built in 90 Decibel Siren, Battery-Backup, Emergency Buttons and 2-Way Voice.
·         ADT Sticker Decals and Signs
·         ADT Guarantees and Warranty Cost:
$49 for Residential Activation plus local sales tax (with a 36 month agreement, with local sales taxes.) $99 Installation FREE System Replacement if necessary $35.99/mo for ADT Monitoring to protect your home 24/7 "
The guy arrived and looked at my windows and said they were not prewired and that it would by $129/window and that builders sometimes tell you one thing but then give you something else.  He was looking for magnets inside the window tracks.  I got my builder on the phone and he explained the magnets were outside the tracks, but were certainly there. So then the installer said , ok, i'll go ahead and install then...So he put the panel in, and then the first keypad and then came to explain that the installation covered the 3 doors, but my 18 windows would be $129 EACH??? They are already pre-wired? All he had to do was hook them into the panel. 

Given the offer above, I feel ADT is practicing questionable sales/marketing practices (bait/switch?).  I asked him to leave and he made a phone call and came back and said, ok $40/window.  That's still $720 more than I was expecting to pay?  I asked him to leave again.   DO NOT GO WITH ADT.