Final answer:
Tying sales require customers to buy one product to be able to purchase another, potentially unwanted, product. These restrictive practices limit consumer choice and competition. Bundling, however, offers multiple products for a reduced price and can be more appealing to consumers.
Step-by-step explanation:
Tying sales happen when a customer is allowed to buy one product only if they also buy a second, unrelated product. These sales are controversial because they can force consumers to purchase additional products that they may not want or need, which are not necessarily advantageous to them.
For example, to buy a popular DVD, a store might require the purchase of a specific portable TV model, even though these products are only loosely related.
Further, such practices are considered restrictive practices because they can reduce competition and consumer choice. In contrast, a concept known as bundling often allows customers to pay a reduced price for a combined offer, such as cable, internet, and phone services, which can be more appealing due to perceived savings.