If you would like to remove a tag along with the text inside it then use the following code.
<?php
preg_replace('/(<tag>.+?)+(<\/tag>)/i', '', $string);
?>
example
<?php $string='<span class="normalprice">55 PKR</span>'; ?>
<?php
$string = preg_replace('/(<span class="normalprice">.+?)+(<\/span>)/i', '', $string);
?>
This will results a null or empty string.
<?php
$string='My String <span class="normalprice">55 PKR</span>';
$string = preg_replace('/(<span class="normalprice">.+?)+(<\/span>)/i', '', $string);
?>
This will results a " My String"
