Here's an excerpt from an email my friend received from Booksurge. They're a self publishing company owned by Amazon.com, and they have their own holiday promotion going too.
BookSurge has a special offer that will jumpstart your work and gives you opportunities for publicity from the beginning. For the month of December, when you sign up to publish your book with BookSurge and purchase Press Release Creation and Distribution Services and a Publicity Pack, you'll receive 50 complimentary trade paperback copies of your book. With Press Release Creation and Distribution services, a professional public relations writer will craft and distribute a press release announcing the publication of your book. The press release is designed to garner media attention, while our Publicity Kit includes 500 each of postcards, business cards, and bookmarks that are ready to hand out at your first book signing.
This deal requires more purchasing though. My estimate is you'll have to spend no less then a thousand dollars to actually get the free books. The iUniverse and Xlibris deals sound a lot better.