Just got back from Target where I saw that they have another great cereal deal going this week:
Buy 4 Cheerios for $11, get a gift card for $5. As is, this would make your cost $1.50/box which is pretty good. But combine it with coupons and it would be stellar.
For instance, if you joined the Cheerios Challenge, you should have received a coupon for a free box, as well as 6 $1 coupons over the course of several weeks. Depending on their expiration dates, you could do this:
Buy 4 Cheerios for $11
Minus free box coupon ($2.75)
Minus 3 $1 coupons.
Pay out of pocket $5.25 + tax
Minus $5 gift card
Get 4 boxes of cereal for a quarter! Whoo hoo! Fits my cereal rule to a T.