For free romance there's
http://www.everyonesreading.com and
http://www.harlequincelebrates.com (That's Mills & Boon and Harlequin, respectively) and
http://www.allromanceebooks.com/category180.html has a list of free offerings from a number of different epublishers.
There are a number of discounted full-length novels from Grand Central each month, those are available at various e-tailers. Here's December's list:
* Orcs by Stan Nicholls $1.00
* Pitch Black by Susan Crandall $1.99
* Seeing Red by Susan Crandall $1.99
* Bad News by Donald E. Westlake $1.99
* Dark Harbor by David Hosp $1.99
* The New Centurions by Joseph Wambaugh $1.99
* Deception by Denise Mina
I'd also suggest checking out
http://www.smartbitchestrashybooks.com and
www.dearauthor.com - two romance focused review/discussion blogs that love ebooks.
As an aside, if she's going to rock the Harlequin or M&B, their pdf format is tough to read on a Sony. I buy my books in MS reader from them, use ConvertLit to remove the drm, then convert to epub in Calibre. I find that yields the most readable book. May be of questionable legality depending on where you live.