Within 3-5 years decent prints will be available for $300-$400. Will they be commonplace in people's homes? Maybe not quite, as they will mainly use plastic only. In 7-8 years I am guessing that cheap printers which can use a variety of materials, wood, metal, plastics, etc will be cheap enough, and then, I believe they will begin invading most people's homes.

Once the stuff used in the printers get cheap enough or printers which recycle trash into filament comes about, things will explode.