You may have earned a PS Membership Download from a promotional event. The opportunity to download an in-house design product for free was automatically awarded to your email address associated with your account.
You will not be charged as a member.
You do not automatically get enrolled into anything.
It is just a free opportunity to try out the PS Member shopping experience.
You'll need to use the PS Membership Download opportunity and have a 0 balance before the website will show prices on any in-house designs.