Is a CeX membership free?

Excuse me, I was wondering about the CeX membership. Is it a free service that customers can sign up for, or does it come with a fee? It's important for me to understand the benefits and costs associated with becoming a member before I make a decision. If there is a cost, can you please elaborate on the various membership options and their corresponding fees? Additionally, could you also highlight some of the perks and privileges that come with being a CeX member? Thank you in advance for your assistance.