What are my options for mobile pay?

With Wal-Mart Stores Inc. becoming the latest retailer to launch a mobile pay system, there are more places than ever to break out a digital wallet to pay for the things you want. Apple, Rite Aid, Starbucks, KFC and others are now using some form of mobile payment system with a smartphone seemingly in every pocket and purse. Forrester predicts that money spent in stores by people using digital wallets will grow from the $4 billion of 2014, to $34 billion by 2019. But not all digital wallets are