The very informative Genie's Lamp has a chart comparing the resource requirements for all Heroes of Might and Magic V factions. The highest and lowest costs for each resource type are highlighted.

The goal was to put things in perspective in the debate about the competitiveness of each town (on the official forum). The Necropolis is very cheap to build up as you will see in the chart.

Looks for the May 7 entry in the latest news.