Security alarm ? Is it possible that I can buy my own alarm system then just pay a company to monitor it?

If so where would I buy the alarm system? And is it the cheaper way to go?

How can I arm my alarm system with out having a monitor company monitor me?

I bought my house with a ADT system alredy instlled. I would like to arm the system when we go to bed at night but I do not know the code and the owners before us do not remember it. I was thinking I could go back to some original 9999 number and start form [...]

Why should I have my home alarm connected to a company to monitor it?

Seems like anyone breaking into my home will run away when alarm goes off. Why can’t I install my own alarm and not pay monitoring?