Having certificates like these helps your resume stand out. These courses are offered through a range of providers so feel free to look around.

Barista certificate ($69-$199, 2-5 hrs in person, 14-16+)

https://abundancecollege.org.au/barista-course/ (autism support provided)

https://www.baristabasics.com.au/?Coffee-Courses;Info;1674 

White Card ($89 for students, for construction / building / gardening / Bunnings etc, often 14+)

https://bluedogtraining.com.au/courses/white-cards/queensland 

First Aid ($89, age requirement for some courses is 14+)

https://www.brisbanefirstaidcourse.com.au/locations/redlands/ 

Responsible Service of Alcohol ($19.90, best for 16+)

https://cleartowork.com.au/rsa-qld-online/ 

Do a free online course, especially one by a university such as those offered through FutureLearn and EdX.

DoFoodSafely - Department of Health Victoria

https://dofoodsafely.health.vic.gov.au/index.php/en/ 

Difficult Conversations in the Workplace - Fairwork Australia

https://www.fairwork.gov.au/tools-and-resources/online-learning-centre/difficult-conversations-in-the-workplace-employee-course 

Payment Security (for cashiers) - Safety Culture

https://training.safetyculture.com/course/payment-security-for-cashiers/ 

Communication and Interpersonal Skills in the Workplace - University of Leeds (4hrs)

https://www.futurelearn.com/courses/communication-and-interpersonal-skills-at-work 

Volunteering at a local op shop, children's program or community event is a great resume filler and a way to give back to the community. Leading in a scouts group, sports club or cadets  program is also encouraged. You can also ask family and friends about doing some work experience at their workplace.

Seek Volunteer (online or in-person)

https://www.volunteer.com.au/volunteering/in-online-or-remote?suitablefor=1%2C8 

GoVolunteer

https://govolunteer.com.au/volunteering