Does the price of a certain product include patent fees? What percentage of the price is the patent fee? Are there any rules for this?

Some are included and some are not included. Different products are different. For example, this product has a higher patent and you have a higher proportion. This patent was developed by themselves or purchased or paid dividends. The situation is different, and the proportions are different. The regulations cannot be said specifically, and it still depends on the manufacturer and patent holder