Confusion about the exam voucher

I recently enrolled in the “Penetration Tester Path,” which advertised that we could earn the certificate after completing and passing the exam.

However, when I enrolled, it didn’t ask me to pay.

Now I need to purchase some cubes to continue with my modules in this path.

I went to the subscription page, and now I’m confused. Should I purchase the HTB Certified Penetration Testing Specialist voucher, which is $210, or should I pay only for the modules that I want to unlock(e.g., $10 for 100 cubes)?

The goal is to spend on the right thing and be able to take the exam. I don’t wanna double-pay by mistake.