It was $17.78 US for the part pictured above (and $6.06 for a smaller 2 x 6 plate of a different material). So, I don't think it would be economical to have a lot of custom parts printed, but I was willing to try it for this one-off experiment.
Shapeways does have an informative page about all the available materials. Prices are given per cubic centimeter. In addition to various plastics, they can produce metal and ceramic objects as well!
Shapeways does have an informative page about all the available materials. Prices are given per cubic centimeter. In addition to various plastics, they can produce metal and ceramic objects as well!