Post Cereal for $1.38 a box Starting 09/24 at Walgreens! Posted by Harbor Master on 20 September 2017, 8:59 am Tweet Expired Starting 09/24, Walgreens will have Post Cereal on sale for $1.88 a box. $1.38 a box when you buy two and use the $1 off two coupons below! The coupons may not be available when the deal starts. Print yours now so you will be ready. 🙂 Click here to print a coupon for $1 off two Post Honey Bunches of Oats Cereal (any flavor) 13 oz or larger Click here to print a coupon for $1 off any two Post Great Grains Cereal (any flavor)