I have a 3D printer (Makerbot 2, not really low end, cost ~$2000), so let me correct a couple of misconceptions in this thread:

1. 3D printed parts can be, and usually are, quite strong. The strength of a part is directional - the parts are much stronger in the direction parallel to the filament deposition than in the perpendicular direction. But door handles and the like are no problem at all. The parts can also be strong and very light, because printing the inside volume as a honeycomb mesh is possible (and is the default option at least on the printer driver I am using)

2. The labout input in actually making a part is minimal, surely less than a trip to the store to buy one. Currently, the labour-intensive part is finding or producing the right design - but once the design is made, it can in theory be available to anyone in the world to use. "Thingiverse" is an attempt to collate the various designs, unfortunately it is full of sub-mediocre stuff and not sufficiently easy to navigate around.

I have literally hundreds of 3D printed objects around me right now, most are models of industrial plants and boats. But I have also made a few everyday objects that I otherwise would have had trouble getting at all, including:

• A control knob for my amplifier, the original was lost somewhere
• A knob for window wiper control for my car
• The little thing that you pull to open the door in the car
• A hard-to-explain bracket that holds a milk shelf in my fridge

Now that i have made the models (and it was fun to do, so was there a labour "cost"?), these things above should be available on the 'net for anyone... I feel kinda bad for not doing that, but the problem is this: How do I identify say the fridge bracket, so that people can find it? OK, its a Fisher and Paykel 350 l fridge, model ABC-1234 or w/e, but then...? Now if the fridge maker provided the design on their web site, we'd be getting somewhere, and if 3D printers have sufficient penetration, perhaps they will one day.