The Actual plastic weight of the parts should be well below a kg (depending on the print settings of course). I am printing a set at the moment, 15% fill. If I remember to weigh it, I will post it here. Remember that the actual value of the parts are not only dependent on the value of the raw material used. Time is also an important factor.
That said, I sell a set of parts to South-Africans for around $60 a set. It helps pay for the filament of the development of the next Morgan derivative.
$100 a set is a little expensive for my taste, but for most people in the first world $100 is affordable enough.