There’s a really good science fiction novel by Robert Sheckley called Immortality, Inc. where scientists in the future have discovered that there is an afterlife, but the only way to ensure you get there is a medical procedure and you can only do that if you can afford it. That’s just the beginning, there’s a huge amount of worldbuilding, but that’s the main theme of the book.
There’s a really good science fiction novel by Robert Sheckley called Immortality, Inc. where scientists in the future have discovered that there is an afterlife, but the only way to ensure you get there is a medical procedure and you can only do that if you can afford it. That’s just the beginning, there’s a huge amount of worldbuilding, but that’s the main theme of the book.