You can get the entire Enchanted Forest series (the name of the series that Dealing with Dragons is the first of; four books in total) for $20-30.

As a male I enjoyed it, and one of my best female friends also remembers it fondly.

I'd also throw in Sabriel, as a YA fantasy novel that I really liked, that had a female protagonist who kicked ass (rather than was there to support a male, or something else equally stereotypical)

I second the Sabriel series. I tend to think Garth Nix is a kind of Neil-Gaiman-starter author. Elements of gothic/horror stuff, but never really too scary for kids (or at least, not for me when I was that age, it tends to depend on the kid in question)

Just as a counterpoint, I have read the Sabriel series, but I was unimpressed.