When a product has multiple price points (for example Small / Medium / Large), this setting controls which one is shown by default on category pages and search results, before a customer opens the product itself.
Go to Dashboard > Products > Product Settings and find Price to Highlight under Product Display Option.
Highlighting a lower price point makes your category pages look more competitively priced at a glance, which can improve click-through to the full product page even though all price options remain available once a customer opens the product.