Open _upgradeBoxes.inc.php
Find:
<?php echo SITE_CONFIG_COST_CURRENCY_SYMBOL; ?><?php echo number_format(str_replace(",", "", constant('SITE_CONFIG_COST_FOR_' . $day . '_DAYS_PREMIUM')), 2); ?>
Replace with:
<?php echo number_format(str_replace(",", "", constant('SITE_CONFIG_COST_FOR_' . $day...