Shop 1 yuan lottery skills

The secret of the lottery of the canteen 1 yuan is that the prices of most products are lower than 1 yuan. In order to promote products, the canteen often holds a lottery of 1 yuan. Most of the products participating in the lucky draw are within 1 yuan, and the merchants will earn profits from the products. Lottery is for publicity and praise, and the meaning of the winner is determined by lottery.