Matt Wade has a great tip posted over on Codewalkers.com about a book going on sale that those just starting out with PHP might want to look into:
My friend Jason Gilmore is selling his popular book (which I also happen to be the tech reviewer of), "Beginning PHP and MySQL 5, Second Edition" via his company website for just $26.99 + $3.50 S/H, which to my knowledge is the lowest price anywhere.
You can check out more about the book and get the full details on how to order from this post over on Jason's blog. Offer is only available only to U.S. residents due to cost restrictions.