Hi, you might find the following site interesting as it is in the UK. - http://www.amazonails.org.uk/. This site shows the lay person how to build using straw bales - ancient methods with new twists and a very inexpensive way to build a house if you own a site.
Also you might like to check out this site for further ideas as the most inexpensive material is used here - clay -http://www.greenhomebuilding.com/cob.htm. This is an American site but very good ideas and will give you great inspiration here.
This next site is in the UK and claims that a man built a house for £500!! Check it out anyway and see how it goes for you.http://www.sustainablebuild.co.uk/CobBuilding.html...
Hope this has given you some new ideas. Thanks for the question.