Does it cost more to use the payment facility and send SMS?
SMS alerts are optional, and incur an additional charge.
For schools/businesses on a subscription, SMS credits can be purchases as needed. 1 SMS credit is deducted per SMS. For schools, there is an option to send SMS message to the primary parent/connection, rather than both parents.
For schools/business on a PAYG plan, SMS credits are deducted from your PAYG credits. 1 credit per SMS.