The most basic product is the Square magnetic stripe reader, which can plug into a smartphone’s charging port or headphone jack to take credit card payments. Customers can get one of these for free ...

The Square Reader, which uses a card swipe to make transactions ... "Square processes Visa, MasterCard and American Express credit and debit cards only at this time," a Square spokesperson ...

Additionally, technology like Square's Tap to Pay on Android lets merchants accept payments without a card reader. Do credit card apps cost money for businesses or customers? While the apps themselves ...