Kaiyuan Bao Tong is ok, a few dollars each. If you don't have a plan, search online, but I will tell you this story:

The legend that the moon mark on Kaiyuan money is the nail mark of the queen originated in the Tang Dynasty, and the earliest legend thinks that it is the nail mark left by the eldest grandson of Emperor Taizong Wende. During Xuanzong period of Tang Dynasty, Zheng Qian put forward this theory for the first time in his note Cui Hui. According to him, Ou Yangxun (Qian Wen Kaiyuan Bao Tong writer and famous calligrapher in the early Tang Dynasty) presented a wax sample of Kaiyuan Bao Tong coins, which was pinched off by Wende's grandson, so there were pinch marks on the coins. Although the book "Cui Hui" has been lost, the record of this matter can be found in Volume 8 "Spring Goods" of Tang Dynasty. Since the "Kaiyuan" round square hole coin was cast and issued in the fourth year of Wude (62 1), it was later suggested that Queen Dou left a nail mark on the coin.

Maybe I think that the grandson of Empress Wende and Empress Dou are still lacking in love, and I mistakenly think that Kaiyuan money was cast during the Kaiyuan period of Emperor Xuanzong of the Tang Dynasty, so someone moved out a dramatic historical figure, Yang Guifei. Because Yang Guifei's fame is greater than that of the eldest grandson queen and the dou queen, the statement of Yang Guifei's scar is more likely to arouse people's interest. This legend was widely circulated at the end of the Northern Song Dynasty. Wang, a scholar at the end of the Northern Song Dynasty and the beginning of the Southern Song Dynasty, disagreed with this statement. However, when he wrote Xue Lin, he also left a record in Volume III, Kai Yuan Qian Ji, that "Kai Yuan has the most money today, which is said to be the money cast by Tang Ming Emperor Kai Yuan, and there is a half-moon handwriting on the back, which is said to be the nail mark of Yang Guifei".