Natural slate today cost between on average $400.00 to $500.00 per square. Slate roofing in the United States today normally runs around $400.00 per square plus the cost of shipping. Some softer weathering or fading slate is less expensive because they are easier to mass produce. Harder unfading slates are more desirable and thus bring more of a premium because it is harder to mass produce. The size of the slate also affects the cost of the material as well as current stock levels. Thicker slate costs are normally higher because there is more material per piece, thicker material is harder to produce, there is more trim work usage and the cost of shipping is higher due to the additional weight of each piece of slate.
Slate jobs are priced out individually because of the variables of product color, size, thickness, quantity, current availability of that requested size, and shipping cost. There is no such thing as a normal cost. One can only give a ballpark figure until the project progresses to a point where more of the decisions are made regarding the different variables. Only then can a true cost be determined for the material. And as we all are aware, in our current time shipping cost are always subject to change.