The alarms are easily installed. They are glued possibly so there are two sensors that match up to each other when a window or door is closed. We have the sensors on all windows that move. There is also a noise detection, so if a window is broken the alarm will sound. At the same time, any loud noise could set off the alarm, much like a car. If the alarm goes off, security calls the house via the key pad and we have to give a name and password. If you don't answer, they will dispatch security.
For $300 I think you should call around. I can understand an installation charge, but a deposit with a contract seems unreasonable. What is the deposit applied toward? Yes our monthly charge is about $35/month.
And yes, it is that time of year for break ins. It always seems to increase when the weather is nice and the doors and windows are open for fresh air.
Be sure to shut your blinds too. You don't want anyone to steak out the house and see what is in there, point of entry, and confirm no one is home.
I was told to talk to anyone who knocks at the door through the door so they know there is someone home. If they think you are not there, they could kick in the door while you are home...not good.