VERIZON BUYING TRACFONE WIRELESS: Verizon Communications Inc. agreed to buy TracFone Wireless Inc. from America Movil SAB for as much as $6.9 billion, as the largest US wireless carrier seeks to expand its mobile business into the so-called prepaid market. Verizon will pay $3.125 billion in cash and $3.125 billion in stock, with as much as $650 million additional tied to performance goals, it said in a statement Monday. TracFone, a US prepaid mobile service, is a subsidiary of Carlos Slim Domit's Mexico-based America Movil wireless. It's the largest US prepaid service, with 21 million subscribers.