I've bought some FASS radomes from Harro (Hobbes on the forums), his Shapeways name is Acme Engineering. The first pair I bought were in 1/120 scale and were priced at around US$30, this was in the second best option. I've just bought another pair plus a pair in 1/50 scale, but the price for the 1/50 in the second best option was US$250+, I got that down to a bit over US$100 by choosing the cheapest option and then because it was still quite a bit expensive, selected the cheapest option for the 1/120 pair, this was priced under US$20.
Harro told me that the prices are governed by the space required to print the object in the printer, so a small object is fairly cheap, but scale it up to something larger, the price jumps up dramatically.