What term describes the desire, ability, and willingness to buy a product at a given price?

The term that best describes the desire, ability, and willingness to buy a product at a given price is "demand." Demand reflects not only a consumer's interest in a good or service but also their capacity and readiness to purchase it at a set price. This concept is crucial in economics because it helps to understand how consumers interact with the market. Various factors can influence demand, including consumer preferences, income levels, and the prices of related goods. Demand is typically represented on a graph where the relationship between price and quantity demanded is illustrated, demonstrating how higher prices may deter purchasing and lower prices may encourage it.

Other terms, while related, do not capture this specific combination of willingness, ability, and desire to buy. For instance, supply refers to the amount of a product that producers are willing to sell at various prices, investment relates to the allocation of resources over time for potential future benefits, and preference indicates a consumer's likes or dislikes but does not encompass the economic concepts of ability and actual willingness to buy a product.