In a market economy, the lowest price and the highest quality for the consumer should result when demand is high, supply is high, and a number of companies are selling the product.
When demand is high, companies have an incentive to produce more of the product to meet the demand, which can lead to an increase in supply. When there are many companies producing and selling the same product, they compete with each other for customers by trying to offer better quality or lower prices. This competition can drive down prices and improve quality as companies strive to gain market share.
In contrast, when demand is low, supply is low, and only one company is selling the product, that company has a monopoly and can charge high prices without fear of competition. Conversely, when demand is low and supply is high, companies may have to compete on price, which can lead to a decrease in quality.
Therefore, the best conditions for the consumer in terms of price and quality are when demand and supply are both high, and there is competition among companies.