Yeah, from the post title here and the opening of the article, I thought this going to be alternative housing on a budget, but instead it was more vanity guest house for the stuffwhitepeoplelike.com set.
Also it's hard to compare the price of something made for the British housing market to prices here in America. It could be the case that housing in general is just much more expensive there.
That said, it does seem way too expensive for the average case, although it might be worth it to me if I could stick it on a green roof somewhere.
If you can get property in the UK and get the rights to put one of these sheds on, you'll probably save yourself anywhere between £25,000 and £100,000 on your lower end priced home.