How much is the handwriting written by calligrapher Zhang?

How much is it worth to comment on calligraphers' works? Such a question is stupid. The real artistic value is not because of the author's age or fame, but the value of art itself. For example, teacher Zhang's works are exquisite and rigorous, and the cursive script is smooth and unrestrained. Different styles have different forms and feelings. There are many high-priced calligraphy works, but how many can reach the realm of Zhang Lao? ...