Square is a mobile card reader company that was launched by Twitter co-founder Jack Dorsey. Square has been growing by leaps-and-bounds and they ended 2012 processing $10 billion annually with 40,000 retail partners.
In August 2012, Square signed a huge partnership with Starbucks to provide the coffee company with credit card processing services using Square Wallet. Square is available at 30,000 retail locations now.
You can buy Square’s readers from AT&T, Walgreens, Staples, FedEx Office, Apple, RadioShack, and Target. Square’s readers sell for $9.99 in stores, but it comes with a $10 credit. Square also has a store locator feature to find out where customers can buy the device.