Is there some way to add an option.... let's say a flat additional $15 fee for something on an entire order, even if the person ordered a quantity of more than one. This $15 fee would be an option for a service done on the entire order.
I don't want them to be charged $15 extra for each item, but just $15 for the entire order. This price may vary depending on the item. For example one item might cost an option $15 for the entire order, and another might be $20 for the entire order.
Thanks to anybody who might be able to help.