I am not sure if I follow. The client clicks on an item, gets an options box from which to select and this indicates the price you specify. If as part of a menu you can set the price to zero. The customer will know what the prices are, is that not being transparent to the customer or even creates excitement of getting something for free? Or do you not want to have clients know that an option costs 0 which they select? If so then maybe removing the following part from cartBox/cart_item_values in the Orange template (can be done via Admin->Design->Select Theme brush->Templates->Partials->select cartBox
<?php if ($optionValue->price > 0) { ?>
(<?= currency_format($optionValue->price); ?>)
<?php } ?>
Not sure if this will solve it, others on this forum most likely know much better s I just got into this appliction!