1. Supply chain advantages: Pinduoduo has established close cooperative relations with a large number of suppliers, directly from factories to consumers, eliminating intermediate links, thus achieving lower prices.

2. Economies of scale: Pinduoduo can get more bulk discounts because of its large purchase volume, enabling it to buy goods at lower prices.

3. Promotional activities: Pinduoduo platforms and merchants often carry out various promotional activities to reduce the price of goods.

4. Cost advantage: direct delivery from Pinduoduo, with no intermediate links, makes the cost lower and the price relatively lower.

5. Store meat: Some beef offal is stored meat, that is, it is stored at the peak of beef production and then sold when the supply is in short supply, which also makes the price relatively low.

To sum up, the main reasons for the low price of beef offal in Pinduoduo are supply chain advantages, economies of scale, promotional activities, cost advantages and stored meat.