How to read the code to know the price of Chinese cigarettes?

There is a secret code on China's cigarette paper, which can be seen by ultraviolet light. "Three prefixes" often refer to the last three digits of the code, such as 320/330. Generally, it is not a prefix 650 yuan/strip, and the prefix price is slightly higher (some people think that the prefix 3 is easier to draw), generally 700-750 yuan/strip.