Many years ago I worked my way through Larry Ullman's "
PHP for the World Wide Web". The book slowly builds a complex website, and trouble-shoots it during the process. Sections like "Top Ten Problems" will save you time by quickly solving the typical beginner mistakes. When things go wrong, you can also get help from his active website with up-to-date errata, downloads and a discussion forum.
This book has been superceded by later variations. You can find a copy in a used book store for only a few dollars. Or try the latest edition,
"PHP and MySQL for Dynamic Web Sites". If you want to learn PHP, you're going to want to learn mySQL before too long.
Working in PHP is great fun. Enjoy!