300 is not allot for an alarm install plus all the extras. Don’t try to knock the price till you have done one yourself. It’s not as easy as you may think and it's very time consuming. Also not just any idiot can put one in, you have to know what you’re doing or you will have a cluster of wires and nothing working properly. I’m not trying to be a dick but come on it’s just like taking you car to a shop for service it’s around the same price an hour for labor. If you let someone do it on the side and they screw something up who’s going to pay for it? Take it to an insured shop and let them do it right.