Sprint has introduced a new pay-as-you-go service which it will begin offering at Walmart stores on Saturday May 15. The new offering called "Common Cents Mobile," one of Sprint's prepaid brands, includes 7- cent per minute phone calls and 7-cent text messages. Common Cents Mobile includes a round down feature, so if a user talks for 1 minute and 46 seconds they will be charged for 1 minute and not 2.