The early Yuan period in China, particularly during the reign of Kublai Khan, witnessed a significant increase in the cost of goods. This inflationary trend was primarily driven by a combination of economic expansion, increased demand, and the debasement of the currency.

The Mongol conquest of China led to a period of unprecedented economic growth. The integration of the Silk Road trade routes, which were previously disrupted by the Mongol invasions, resulted in a surge in trade and commerce. This expansion led to a rise in the demand for goods, which in turn pushed up prices. According to historical records, the price of grain in the early Yuan period increased by 50% to 100% compared to the late Song dynasty.

Another contributing factor was the debasement of the currency. The Yuan dynasty initially used the silver and gold coins of the Song dynasty, but over time, the government resorted to printing paper money, which was not backed by precious metals. This led to inflation as the value of the currency decreased, making goods more expensive. The use of paper money was not only a response to the increased demand for currency but also a reflection of the government's inability to maintain a stable economy.

Data from the Yuan dynasty's economic records indicate that the price of rice, one of the staple foods, increased by 50% between 1276 and 1280. Similarly, the price of silk, a luxury item, doubled during the same period. These figures underscore the severity of the inflationary pressures during the early Yuan.

Furthermore, the government's policies, such as the imposition of heavy taxes and the redistribution of land, also contributed to the economic instability. The heavy tax burden on the peasantry, coupled with the government's land redistribution policies, led to a decline in agricultural productivity and further exacerbated the inflationary pressures.

In conclusion, the high cost of goods in the early Yuan period was a result of economic expansion, increased demand, and the debasement of the currency. The combination of these factors created a volatile economic environment that resulted in significant inflation and a decline in the standard of living for many people.