You see, I joined the Cheerios Challenge a couple of weeks ago and ever since they have been emailing me a new $1/1 coupon every week. Now, since it is a "bricks" coupon I am able to print two coupons every week (just press the back button on your browser after the first one prints and click yes to resend data).
I have found a couple of sales for Cheerios since I've begun receiving the coupons, but Walmart sells their big 18 oz. boxes for $2.50 (that's $.08 an ounce after coupon) which makes for some cheap cereal. And, Cheerios are one of the healthiest cereals out there!
Manufacturer websites are an excellent source of coupons and samples. Google some of your favorite brands today (just look for a promotions or coupons label on their main website) and join the Cheerios Challenge for lots of cheap cereal!