1. Platform subsidy: Pinduoduo platform has a strong subsidy for fresh products, so snail powder, as one of fresh products, can be sold at a lower price than other platforms.

2. Direct supply: buy more vegetables, cooperate directly with snail powder suppliers, without going through intermediaries, which can reduce costs and ensure the quality and freshness of products.

3. Small profits but quick turnover: buy more vegetables with the strategy of small profits but quick turnover, and attract more consumers to buy through low prices, so as to obtain more profits.

Generally speaking, snail powder in grocery stores is cheap because of the comprehensive effects of platform subsidies, direct supply and small profits but quick turnover.