1. Determine the price paid by the user. The price does not include the packaging fee paid by the user. The paid price is equal to the cost plus the distribution fee plus the activity expenditure.

2. The mantissa pricing method is a very common pricing method, that is, the food price of 20 yuan, 30 yuan and other integer multiples of the original price is set as 19.8 yuan and 29.8 yuan, so that the number at the end of the price changes accordingly.