Multipod Studio (a French architectural firm) recently unveiled a new sustainable house prototype that's lightweight, recyclable, and promises to be an inexpensive purchase and extremely efficient to run. The suitably-named Pop-Up House also boasts another notable selling-point: all that's required to assemble it is four day's patience and a standard electric screwdriver.
At present, Pop-Up House is still in the prototype stage, so finer details on the home are lacking. A preliminary price is available though, and the home will set you back €30,000 (roughly US$41,000), which includes labor, but doesn't include finishing touches like waterproofing, electricity, and plumbing.
You can see an overview of the project in the video: