Wireless Security Alarm

Well, I am kind of interested in possibly getting a cctv spy camera such as the one on this ebay auction http://cgi.ebay.com/Wireless-Color-Pinhole-spy-Security-Camera-CCTV-system_W0QQitemZ250118499692QQihZ015QQcategoryZ14957QQrdZ1QQcmdZViewItem.
However I don’t really know much about them except for the fact that theyre small and wireless. What else should I learn about them? How does the wireless work? Does it need like an internet adapter? If you could answer any of these I would really appreciate it, thanks

Seller is selling a vehicle back up device.
It has been repackaged in box.
He has 100% feedback.
Do you think its broken, so that is why he is selling it?

http://cgi.ebay.com/Vehicle-Back-Up-Camera-Wireless-System-3-5-LCD-Screen_W0QQitemZ310007337605QQihZ021QQcategoryZ149976QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

This is a system that’s much cheaper in price than some do it yourself sytems. Looks like a lot of them have sold on Ebay. Does anyone know if the system actually works? How well with dogs running around the house?

I never bought a camera before. Which one should I start with? Should I buy on Ebay or go to a local store? How dificult is the installation?

Im looking to buy a twin cctv setup for my home, a wired black and white setup with night vision would be fine tho id pay the extra for colour and wireless if it wasnt a big difference, anyone have any ideas for a good system, ive seen the ‘GET’ systems in Homebase and B&Q and they’re around the £80 mark tho ive seen systems on ebay from £5 upwards?