CCTV kit is certainly an affordable home security measure for most budgets now, and adds a really effective layer to any system that attempts to prevent a home intrusion and the impact this may have, whether to the occupants safety or to property.
Although the range of options is massive, classic CCTV kits typically come with one or more cameras and a recording device, normally nowadays a digital video recorder. You will often have the option of including a monitor so you can study the footage yourself.
Extra options that are available are night vision or infrared cameras, motion activated cameras, and PTZ or Pan Tilt Zoom cameras to allow you lots of flexibility in your range of view.
Some CCTV camera kits will be wireless, others will require a wired installation. Both have pros and cons, and the debate rages on as to which is preferable. Wireless CCTV kits are certainly much more easy to install, so much so that a professional installation is rarely necessary if you have some basic DIY skills. This ease of installation also means the install will be cheap. A wired system may require knocking through wall, laying cable, possibly underground if you are linking outbuildings in to your security set-up.
On the flip side though, a wired system is purported to be more reliable, and there are no issues with possible weak transmission of the radio signal between the camera and recorder.
To make any system a little more affordable, there is the option of supplementing or completely replacing operational cameras with dummy cameras. If a combination is preferred, always point the real cameras at the most likely entry points such as doors and accessible windows, and save the dummy devices for less important areas, perhaps an outbuilding or covering the wall of your garden.
Another consideration is the primary use you intend for your system. Cameras obviously have a deterrent effect on would-be criminals, and for this to work effectively, they need to be positioned prominently so they are easily seen. They can also be backed up by additional signage that confirms that the property is under surveillance.
In contrast, there is sometimes a need to set up a system that is covert. The cameras are hidden and it is not obvious that the area is being monitored. This works in some business environments where staff need to be observed, but it is generally less used than the deterrent option in a home setting.
Whichever options you go for, check the warranty, any installation and parts packages that are available and ongoing support arrangements.