What is a common requirement for labels on product containers sold at a farmers' market?

The inclusion of the price per unit on labels for product containers sold at a farmers' market is a common requirement because it helps inform customers about the cost of the products they are purchasing. Transparency in pricing encourages informed purchasing decisions and fosters fair trading practices between vendors and consumers.

While it is beneficial for products to have expiration dates and nutritional information, these requirements can vary by location and product type and may not be universally mandated for all items sold at farmers' markets. Therefore, the price per unit serves as a standard requirement that is consistently applicable across different products and markets, ensuring that consumers can easily compare prices.