Sprint prepaid brand Common Cents Mobile has expanded into an additional 500 Walmart stores in several new markets, including Chicago, New Orleans, Cincinnati and Washington, D.C.

The expansion brings the budget phone service to nearly 1,250 Walmart stores nationwide.

Common Cents is marking the occasion with an additional 200 minutes of domestic calls for new customers refilling their phone for the first time.

The bonus minutes come with the “round down” feature of Common Cents’ other minutes, which rounds down the amount of seconds used by a customer after the first minute of use. For example, if a customer talks for 3 minutes and 23 seconds, only 3 minutes will be deducted from their total minute usage.

Common Cents was launched in May and markets its services on simplicity and cost. The pay-by-the-minute service offers just three phones and it claims its rates are some of the lowest on the market, with 7 cents per minute and 7 cents per text, picture messaging, e-mail or instant message.

Sprint’s other prepaid brands include Virgin Mobile USA, Boost Mobile and Assurance Wireless.