Bloomberg reported today that mobile POS start-up Square will expand its retail presence by making its credit card readers available through Wal-Mart Stores Inc.

The reader is currently available online at the company's site and through several retail outlets like Radio Shack and Target. The retail cost of the credit card reader, which plugs into an Android or iOS device's audio jack turning the device into a credit card reader, is $9.99. According to Bloomberg, adding Wal-Mart as a retail outlet means Square is now available in more than 9,000 locations.

The Square reader, when combined with the Square app and merchant account, gives small businesses the ability to accept credit and debit cards for payment. Square charges its merchant customers 2.75 percent of every transaction made.

Square recently raised $100 million in venture funding, pushing its valuation to more than $1 billion.

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