What is the calligraphy price of China calligrapher Sun Gentang?

Sun Gentang, Zi Ziyuan, 1955, a native of Weifang, Shandong, majoring in secretarial science at Beijing Humanities Correspondence University, is a famous calligrapher. His works spread all over the country, Europe and Asia, and at home and abroad, and won the favor of Chinese and foreign friends. The collection price is about 5000-20000/ square foot.