As per question, is it safe to store passwords on php pages such as
$password = \'pa$$w0rd\';
If the users can\'t see it, it\'s safe, right
Depending on how you define safe, any approach has its positive and negative aspects.
If you really want to store a password in your source, it might be a good idea to do something of the sort:
File: config.php
if( ! defined('IN_CODE') ) die( 'Hacking attempt' );
define( 'PASSWORD_HASH', '098f6bcd4621d373cade4e832627b4f6' );
File: index.php
define( 'IN_CODE', '1' );
include( 'passwd.php' );
if( md5($password) == PASSWORD_HASH )
...
Plain-text is never a good idea, always store a hash of the password you want to store.
Furthermore, try to seperate defines like this from your main sourcefile.