The cost of uniforms varies between schools - some have a casual uniform of a sweater and skirt or trousers, while others have extra clothing like jackets and shirts. In colder climates, there may be both a summer and a winter uniform. Ask the school about this when you visit. You can usually buy school uniforms at department stores or clothes shops. You can also buy them second hand.
Most schools run a second hand shop from the school.
Ask your school for advice. In Australia children travel to school on foot, bicycle, in cars and on public transport. Depending on how far your child lives from school you will need to make appropriate arrangements so that they can be at school on time. Many private or non-government schools hire buses to transport their students to school. A cost will still apply for these services.