I read a few months ago when they released Google Home in the US, they said they would be bringing Google Home to the UK in 2017.
Google is actively adding third party services to Home and negotiating with many other potential providers. They are pulling out all the stops to get the Developers on board so that by the time they do enter the UK (hopefully very soon), they will have a very robust offering.
Meanwhile, as mentioned in an earlier post on this subject, they are soon bringing some of Google Home voice features to the Pixel.
The retail price in the US is $ 129. During Christmas I saw a $ 99 promotion advertised.
My guess is that they way Google will make money on the device (as they will on other voice activated devices like Pixel) will be eventually by charging a service/introduction fee to the party providing the service---eg, Dominos Pizza, Uber, etc-- although I have not seen this confirmed yet. The service will therefore be free to the user.
With many of my expected voice actions on Home expected initially to be search queries (eg, the way I use Google search everyday now), I expect Google will dominate this space as it is a natural search engine which Amazon is not.