You can sell old MetroPCS cell phones through classifieds sites such as Craigslist.org or auction sites such as eBay.com as well as on specialty cell phone buying sites such as Swappa.com, as of 2015. Amazon.com allows customers to sell phones through its Amazon Marketplace program, and it buys certain models as well.
Craigslist.org's For Sale section houses numerous categories for items ranging from clothing and furniture to electronics such as cell phones. To sell a phone through the site, locate the regional page for the city or county where you live, and create a listing that includes a price and a description of the phone, along with optional pictures. While Cragislist.org does not require the creation of an account to list an item for sale, a Seller's Account is necessary to do so on eBay.com. Additionally, the seller needs to link a verified PayPal account in order to handle fee payments.
Swappa.com allows owners with select models of MetroPCS phones to mail the devices to the company in exchange for a flat payment based on the phone's condition. Amazon.com offers a similar program, with payments only available for recent models in acceptable condition. It is also possible to create a Merchant account with the site to sell the phone directly through Amazon.com.