When choosing a pricing strategy, firms may also use various pricing tactics to enhance their performance and influence their customers' perception and behavior. Price skimming, for example, is a tactic where firms charge a high price for a new or innovative product, then gradually lower it over time as the demand declines or the competition increases. This can help them recover research and development costs, segment the market, and create a premium image for their product; however, it may attract new entrants or imitators and alienate price-sensitive customers. Price penetration is another tactic which involves charging a low price for a new or existing product and then increasing it over time as the demand grows or the competition decreases. This can help firms gain market share and increase customer loyalty; however, it may erode their profit margins and trigger a price war. Price bundling is when firms offer two or more complementary products or services together at a lower price than if they were sold separately. This can help them increase their sales volume and create value for customers; however, it may reduce their profit per unit and limit customer choice. Lastly, price discrimination is when firms charge different prices to different customers or groups of customers for the same product or service based on their willingness or ability to pay. This can help them maximize revenues and profits, segment the market, and capture consumer surplus; however, it may face legal or ethical issues and cause customer resentment.