Proof that it's easy to make fabulously expensive models easily with Mineways: size matters. This one's scaled to print out in color, so really adds up in cost, even with the base being hollow.
That said, I didn't spend time making sure all the rooms inside the castle were filled in, so that they could be hollowed out later - I didn't think anyone would actually print this model out! Sarconix did, as a surprise. I suspect I could have saved maybe $20 by placing torches at room doorways and then using the "seal off entrances" option to fill the rooms (which would then get hollowed).
Model built by Sarconix in Vokselia, vokselia.com