[php] How do you get the path to the Laravel Storage folder?

For Laravel 5.x, use $storage_path = storage_path().

From the Laravel 5.0 docs:

storage_path

Get the fully qualified path to the storage directory.

Note also that, for Laravel 5.1 and above, per the Laravel 5.1 docs:

You may also use the storage_path function to generate a fully qualified path to a given file relative to the storage directory:

$path = storage_path('app/file.txt');