Be carefull - setting a locale which uses commas instead of dots in numbers may cause a mysql db not to understand the query:
<?php
setlocale(LC_ALL,"pl");
$price = 1234 / 100; // now the price looks like 12,34
$query = mysql_query("SELECT Id FROM table WHERE price='".$price."'");
?>
Even if there is a price 12.34 - nothing will be found