$14 in sandstone which is pretty rough, or $22 for a pair, already sanded and polished which is the most plastic like option.
http://www.shapeways.com/model/512906/p ... -v1-1.html
Note that in the most updated version, the outer tubes have been increased in diameter to be historically accurate. Thanks to PH for pointing that out!
21st Century Panzer IV RC with Battleground Toys Idler:

21st Century Panzer IV with Stug IV Conversion from the Hun and Battleground Toys Idler:

21st Century Panzer IV with Wirbelwind Conversion from Pickelhaube and Battleground Toys Idler:
