Difference between HDP Overview: Apache Hadoop Essentials - Self Paced Training and the HDP Overview: Apache Hadoop Essentials - Paid Training ?

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I was wondering what is the difference between HDP Overview: Apache Hadoop Essentials self-paced version and paid version ?
I am preparing for the fundamentals exam, so any help or hint regarding the preparation for the Hortonworks Associate Certification (HCA) Exam is appreciated! Thank you.