Wal-Mart Stores often relishes the role of price disruptor, and the retail behemoth has now turned its penny-pinching attention to the business of transferring cash. That has caused great distress for MoneyGram, a Walmart partner for transfers and now newly minted rival, as well as other incumbents. When the Walmart-2-Walmart money-transfer service launches at 4,000 US locations on Thursday, it will cost $2 less than the $11.50 MoneyGram charges to move $50 to $200 between any two stores. The retailer is working with Ria, a provider of money transfers. MoneyGram CEO Pamela Patsley said her company won't match the lower prices -- at least initially. MoneyGram will remain very measured, disciplined, and targeted in its response to competition. That's always been a tenet of their business.