The application, which can be downloaded for free, charges vendors a credit card processing fee of 1.8 percent plus 15 cents per transaction, assuming you're swiping plastic from MasterCard, Visa or Discover.
Pogue also reported that Square, which was started by one of the co-founders of Twitter, only charges 2.75% plus 15 cents per transaction, which is considerably less than typical credit card merchant and set up fees.