That's not a large sum of money, considering that it took about 6 months of nights and weekends it took to write the book, but it isn't nothing either.
Here is the correct link: https://www.packtpub.com/application-development/d-cookbook
It would probably be a good idea for HN to recognize <URL> and "URL", since those are specifically mentioned in RFC 3986 as common ways to delimit URLs in text.
In fact she's just received mid four figures for about two weeks of repurposing - i.e. cutting and pasting - content that was already written and needed some reformatting and light editing.
This isn't common, but it does happen.
A few hundred dollars is more of an insult/negotiating wipe out than a real advance.