A lot of these responses don't really flesh out your question. I'm a security technician, and you're not asking too much.

So, firstly, a security system and a camera (CCTV) system are two separate systems and it helps to speak about them that way, as you can have one without the other.

You can absolutely get a security system that will do what you want. You can get the parts and put it together yourself, which isn't hard and I will help with what equipment to get and guidance on installation and programming. Or, you can contact a local alarm company and tell them you don't want a contract and are willing to pay for the equipment up front, and they will sell it to you, the only benefit here is that they probably have the majority of equipment you want on hand, like the main panel (brain for security system), the keypad, sensors, wireless receiver (unless you want to retrofit wiring into your house), backup battery, etc.