Now you can learn at Atlassian University for less. They changed the price of their basic trainings, and now they are free or starting from $39.
The whole catalog of free and cheap courses is here: https://university.atlassian.com/student/catalog/list?category_ids=21723-on-demand
If you do not have any experience with Jira or Jira Service Management I recommend starting with free courses:
- Get Started with Jira
- Jira Fundamentals
- Jira Service Management Fundamentals
- Basic Jira navigation
- Jira best practices
If you will work with Confluence:
Those are basics, but it’s really hard to work with Jira/Confluence without them.