Is it also available for a custom field? Could you please tell me if not, the code in order to achieve it? Which means if I leave empty a custom field price to display a "call for price" message?
thanks in advance
The custom field has used a language string "Free" for customs that dont cost extra.
You could change the language string,
or do a strip and replace.
views/productdetails/tmpl/default.php
<?php $field->display = str_replace( 'Free', 'WHAT-U-WANT-HERE', $field->display ); ?><?php echo $field->display ?>