This topic is a little bit odd, and maybe not that generally applicable, but I am building a model on commission, and they want a price estimate. Trouble is, the model has not been built yet, so I sort of have no way of knowing how much it will cost. I was thinking about just applying the 10 cents per part cost to it, but I am kind of worried that that approach is too simplistic. I have tried looking at comparable MOCs on Rebrickable, and then using the Bricklink price checker, among other things, but my Google-Fu has failed me, which makes me think that this is something that has not been done before.
A similar issue is if one desires to purchase all the parts for a MOC that has instructions, as discussed in the thread about Gerger's GMK 2400 crane. Effectively, is there any good to estimate the price of a MOC, or is it really just a crap shoot?