Through 5/21, Shutterfly is offering 12 FREE Custom Photo Thank You Cards when you use promo code FREETHANKS during checkout. (You can choose between 6×8, 5×7, 4×5 flat, 5×7 folded, or 3×5 folded cards).
This offer is available for new and current members. Shipping adds around $4.99, but this is still a nice deal!