3. Why would Amazon.com, which has no physical retailing presence, be as interested in encouraging cell phone trade-ins, same as RadioShack and Target? Every year, millions of consumers answer the call to upgrade their cell phones—and that means deciding what to do with the used cell phone being replaced.

Some people reuse their cell phones by giving them to another family member or saving them in case the new phone happens to break. Others simply toss their old cell phones into the trash, even though such electronics have materials that shouldn’t be in landfills. What else can consumers do with their old phones?

One option is to trade it in. Retailers such as Target, Costco, RadioShack, and Amazon.com have trade-in programs that give consumers store credit for used cell phones in decent shape. Another option is to sell the old phone. Sometimes the sale is to an individual, handled privately or via sites such as ebay.com. More often, consumers prefer the convenience of selling to a business that refurbishes and resells electronic goods (or recycles them responsibly if they have no resale value).

Michigan-based ReCellular is among the market leaders in this industry, with $100 million in annual revenue. Consumers click to the company’s website, look up the phone’s make and model, indicate the condition of the phone, and see how much ReCellular will pay for it. To complete the transaction, they download a prepaid shipping label and send the phone to ReCellular, which confirms the condition and then mails payment. The company deletes any personal data, makes any needed repairs, replaces worn or missing parts, tests the phones to ensure they’re in good working order, and then sells them to consumers in domestic and international markets.