Sydney Catholic Schools runs a BYOD Purchase Portal (in conjunction with Mac1 and other retailers) for use by parents. This is a good place to start to look for appropriate devices and their approximate costs. You are not required to purchase through this portal; it is simply intended as an option which may make BYOD selection and purchase simpler for some families.
Many families may find themselves purchasing multiple devices if they have more than one child at school. While buying devices up-front often works out more cost-effectively and allows you to take advantage of sale prices, there are other options which allow you to pay for devices over time. For example, many retailers allow you to pay monthly interest-free repayments. Flexi-rent through retailers such as Harvey Norman and Mac1 often covers damage, loss or theft (at a cost) and a loan or replacement device. Apple also offers a selection of certified refurbished computers at a reduced price, with 1-year warranty. Families who find themselves unable to afford any of these options are encouraged to make an appointment with the Business Manager so that an alternative arrangement can be made.