Amazon has the 16oz General Mills Franken Berry Breakfast Cereal for $3.28 - 5% off with Subscribe & Save (can cancel at any time) = $3.12 with free shipping on $35+ or with Prime. Also on sale for the same price after S&S:

• 18.8oz Count Chocula Cereal with Monster Marshmallows
• 16oz Boo Berry Cereal with Monster Marshmallow