Staples is selling again discounted iTunes gift cards at 15% off. Offer Expires on 01/21/2017. If you have a Chase Ink card you can also get an extra 5x in UR points.
iTunes limit of $500 per day total purchase and a limit of 3 per each gift card. So you should be able to purchase 3 of each in one order.
Staples DOES NOT sell more than $2000 of gift cards in any order due to Federal anti-money laundering regulations.