Final answer:
Cellular phone companies offer discounted or free phones to gain phone services contracts and generate revenue from associated services that exceed the revenue from the phones themselves.
Step-by-step explanation:
In the case of cellular phones, the physical product is practically given away to gain the phone services contract. This is because the revenues from associated services exceed the revenues from the cellular phones. Cellular phone companies offer discounted or free phones in order to attract customers and generate revenue from monthly plans, data usage, and additional services.