Add the option for the buyer to select "Send as Gift" during check-out. Then, on the back-end from Admin side, have the option to print the
Have the option from the check-out page for the client to check "Send as Gift." Then, only if the buyer checks this option, to have the invoice print with no prices. Don't make us have to select an invoice to print with no prices, but have the system automatically print invoice with no prices as long as client selects "send as gift" during check-out.