Hundred gold refers to the approximate price.
Example:
In the Tang Dynasty, Liu Gongquan's calligraphy was probably the most valuable. Sometimes, there is a saying that "a word is worth a hundred dollars, not empty talk", which is even more popular among the people, saying that "a word from Liu is worth a thousand dollars" Although these elements are exaggerated, there is no doubt that his pen fee is very expensive. At that time, ministers and people of some status wrote epitaphs. If you can't get Liu Gongquan's handwriting, it will be considered unfilial, which shows its popularity. Not only that, but also his calligraphy is very famous. When foreign countries come to pay tribute, they arrange a sum of money, which reads: "This is a willow book". From this point of view, even the "book saint" Wang Xizhi is hard to reach.