3D printing is rather useful in the research lab. For example, most biological research labs will have a piece of kit called an electrophoresis chamber. This is essentially a plastic, watertight box with two wire electrodes inside. These chambers will cost upwards of 800 dollars.

I drew up plans for my own electrophoresis chamber in Sketchup, uploaded it to Shapeways (https://www.shapeways.com/model/1240729/sds-page-tank-v6.htm...), and got it printed and sent to me for less than 70 bucks. Wiring it up cost less than a dollar.

By the way, does anybody know of similar services that are even less expensive? Shapeways seem to specialize in making little trinkets and gadgets, so I suspect my rather large, bulky box cost even more than it needed to.