Can someone ELI5 how decentralized websites work and how much it costs or provide a link to some article?
How much it costs? Depends on how you "keep it alive" in the network. There always needs to be at least one person with a copy of the website. If it's you, it's for free - but you can pay a service.
Here's an introduction article: https://almonit.club/blog/2020-05-21/Introduction_to_Dwebsit...