The Straight Talk service, which will include an unlimited calling plan for $45, will be available for purchase at more than 3,200 Wal-Mart stores starting Sunday. The $30 monthly plan includes 1,000 minutes, 1,000 texts, 30MB of mobile Web access, nationwide coverage and 411 calls at no extra charge. With the average U.S. adult spending $78 a month for 1,000 minutes, the Straight Talk plan could save a cell-phone user more than $500 a year, Wal-Mart said. The $45 monthly plan includes unlimited minutes, unlimited texts, unlimited mobile Web access, nationwide coverage and unlimited 411 calls at no extra charge. Straight Talk was developed with TracFone Wireless and initially began as a pilot program at 234 Wal-Mart stores last summer. 'In light of the savings customers continue to need, we have worked very quickly to extend this offering to all of our Wal-Mart customers nationwide, and just before the holidays,' said Greg Hall, Wal-Mart vice president of Media Services. 