You can pre-authorize a payment amount on your credit or debit card which can then be used by your child at the fair.
After approval, a barcode will be available for printing (click “Print receipt” button). The cashier at the book fair can then scan that for the purchase. Only the amount used will be deducted from your account.
You will first be directed to sign in. If you have not registered yet, you will need your school’s “code” to do that.