note 102589 modified in function.preg-replace by danbrown

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"

--was--
If you would like to remove a tag along with the text inside it then use the following code.

preg_replace('/(<tag>.+?)+(<\/tag>)/i', '', $string);

example
$string='<span class="normalprice">55 PKR</span>';

$string = preg_replace('/(<span class="normalprice">.+?)+(<\/span>)/i', '', $string);

This will results a null or empty string.

$string='My String <span class="normalprice">55 PKR</span>';

$string = preg_replace('/(<span class="normalprice">.+?)+(<\/span>)/i', '', $string);

This will results a " My String"

http://php.net/manual/en/function.preg-replace.php