This kind of information you can find on Export Portal site, but you can always contact their customer service department in order to find the right answer for your questions, they are always at your disposal.
If you are a Verified Seller/Manufacturer then you will pay nothing. But if you would like to become certified then you will pay. To pay the upgrade bill: 50 USD per month or 550 USD per year. I will kindly recommend you to become a Certified Seller, you will get more buyers. Also, you can sell more products, gain more exposure, and receive a free EXIMA membership.