What fee does Sherlock Holmes ask from the King of Bohemia?

As we can imagine, the King of Bohemia is very pleased at Holmes's ace detective work. (Not to mention rather relieved at being spared what would've been an almighty scandal). He expresses his immense gratitude by giving Holmes an expensive emerald snake ring. However, Holmes gracefully declines this generous gift, preferring instead a photograph of Irene Adler. Irene's clearly had a profound effect on the world's most famous detective. Although he prevented her from causing a huge scandal, she nonetheless managed to give old Sherlock the slip, and that's not something that many people can say.
It's fair to say that Holmes has more than a sneaking admiration for Irene. For one thing, he's never come across a woman as smart as her. (Or maybe he just hasn't been looking hard enough). In any case, in the figure of Irene Adler Holmes has finally met his match. From now on, he will always describe her, with great reverence, as "the woman," as if she's the only woman in the whole wide world. Indeed, to Holmes, that's precisely what she is.