How much does it cost to sell a game on GOG?

Excuse me, could you please clarify the costs associated with selling a game on GOG? I'm interested in knowing the specific financial requirements or fees that might be involved in listing a game for sale on their platform. Are there any upfront costs, percentage cuts, or other expenses that I should be aware of before embarking on this venture? I'm looking to get a clear understanding of the financial implications so I can make an informed decision about whether selling on GOG is the right move for me. Thank you for your time and assistance.