To test the attractiveness of a product and the willingness to pay before launching it on the market. 

A pop-up store is an innovative tool for testing and refining business ideas in a real-world setting. As a temporary physical point of sale, it allows companies to experiment with product offerings, customer experiences, and market strategies. By engaging directly with customers, businesses can gather valuable insights into product appeal, pricing strategies, and consumer behavior. This hands-on feedback helps inform decisions on product development, marketing, and distribution ahead of a broader launch. Additionally, pop-up stores foster agility and creativity, encouraging businesses to prototype retail concepts, test new markets, and adapt quickly based on learnings. Their temporary nature makes them a cost-effective and impactful method for validating assumptions and reducing risk in product and market development.

Depends on the individual situation; at the least the product(s) and a selling place/shop.