There are different fees depending on the payment method used with Square. Square charges 2.65% per transaction for insert, swipe and NFC, with an additional $0.10 or Interac tap.
These fees are deducted from the payment, not added to the total. For example: by selling a $10 ticket, you will get ~$9.7 (depending on the payment type). Learn more about Square's Fees.
Tip: You can create an additional fee onto each order to cover the Square fees. You can learn more on how to add additional fees here.
To use Square with BoxOffice please follow our guide: Use third-party credit card readers with BoxOffice