seconded. The MMS:WE system boils down to one formula which, if I remember correctly is:
(1 + interior style modifier + exterior style modifier)
x ( ( 1+material modifier) x Sum of (square footage x type cost x height modifier) + carriage cost)
So you decide how big you want, find the cost of the given type of structure/room (e.g. kitchen, fortification, wall, temple, etc), check the multipliers for the materials (stone, wood, etc), decide how available those materials are (carriage=transport of supplies) and decide the interior and exterior styles. You use a handful of tables to pull those modifiers and then punch out the answer.