Who couldn't use some free wireless minutes these days? Cincinnati-based grocery chain Kroger is teaming up with i-wireless, an MVNO on Sprint Nextel's network, for a national promotion that will allow customers who use the KrogerPlus grocery card to get free airtime minutes on i-wireless phones sold at Kroger stores. Customers will get 20 free minutes for every $100 they spend a month while using the card, with a cap of $1,500 a month. Those using Kroger's branded MasterCard will get 30 minutes of airtime for every $100 spent. The program will be available in Kroger's 2,300 stores across 31 states by the end of this month. Article