TRADE UP: Wal-Mart Stores Inc. is launching a program that allows consumers to trade in their existing smartphone for a newer device.

PROGRAM DETAILS: Consumers can trade in a working, undamaged phone for a credit of $50 to $300. The credit can be used to help buy a new phone from a selection of more than 100 devices. Phones can be traded in at participating Walmart stores and Sam's Club locations.

START DATE: The program begins on Sept. 21. Consumers must enter a two-year contract for the new phone with AT&T, Verizon Wireless or Sprint.