Amazon has 12-Pack 6-Oz Annie's Shells & White Cheddar Macaroni & Cheese for $13.48 - 5% off when you check out via Subscribe & Save - 20% off when you clip the coupon on the product page = $10.11. Shipping is free w/ Prime or on orders $35+.
Also available (prices after applying 20% off coupon + 5% off S&S):
Also available (prices after applying 20% off coupon + 5% off S&S):