San Francisco Wal-Mart Stores said it plans to offer two no-contract, low-cost mobile phone plans.
For $30, Walmart is offering 1,000 minutes of calls, 1,000 texts and some Internet access. For $45, buyers get unlimited calls and texts nationwide, and unlimited Web access.
More than 3,200 Walmart stores in the U.S. will sell the Straight Talk prepaid service starting on Sunday.
Some analysts believe Walmart could steal sales from competitors by expanding the availability of low-priced plans.
Last summer, Walmart tested the Straight Talk plan in 234 stores.