The kit is so simple to install and can be easily extended with various optional units. Apart from providing WiFi around the house it also can provide line connections to the Internet for all your PC equipment, TV, games consol and so on. The system uses your electric ring mains. A master unit is connected to your router and the mains and all subsequent unit you install anywhere in your electrical system will pick up the signal. Easy. I have just installed my second set after moving house and now coverage all over the house. Even the blackest of spots can be covered ( like my garage) by unplugging a unit and moving it to a socket near where you are working. If you live in a bungalow try putting a unit in the loft, ceilings are much thinner than walls and therefore you may get excellent coverage in most rooms with only this one unit from the starter kit.
I think this is a fantastic kit and beats cabling your house. As far as price goes I think it is reasonable for what you are able to do.