The small vendors are small businesses with very small profits and fierce competition. Customers buy things at the cheapest price. They don't buy it if they don't give it cheap.
When my uncle sells vegetables in the market, customers will ask for the price. Every vegetable is asked again. The price increase rate for uncle's vegetables is not high. A catty of vegetables earns 1~2 yuan, but the customer still doesn't buy it.
In fact, customers also know that selling vegetables is not easy, because they are used to bargaining in their hearts. When encountering all kinds of customers who are hesitant, the uncle can only sell it cheaper and the income will be reduced.