How much is a flat foot of calligraphy?

I asked Mr. Zhang the price of his calligraphy works before, which is generally not less than 2000 square meters, but the specific price of each work depends on the situation! Because there are many aspects to be considered in painting and calligraphy works, it is unscientific to evaluate the price of works from the aspects of exquisiteness, theme, social influence, age and size. All factors reach a certain standard, which may be eleven thousand square feet high!