Cereal...Bagged VS Coupons..Which is cheaper?

In my house we go through cereal like CRAZY!  Before I started couponing I would purchase the bags of cereal.   Once I started couponing I would buy whatever box cereal that was on sale and I had a coupon for.  Here is a cost break down of Bagged VS Sales/Coupon at Save Mart

Save Mart Sale:
Kellogg's Corn Flakes/Frosted Cinnamon Toast Crunch   12.3oz              Price $1.44
You could use one of MANY print/paper coupons.  I chose to make it fair and just use the sale price

Moms Cinnamon Toasters           19.5oz                                                     Price $2.99
Moms Frosted Flakes                    37 oz                                                      Price $4.95


Kellogg's $.11 per/oz
Moms (store brand bagged cereal)    $.13 per/oz  and $.15 per/oz

Now just think if I had added coupons to this deal.   I do have to say there are times when bagged is cheaper.  Winco will "close-out" their bag cereal for $2.98 each and then it will likely be cheaper to purchase the bags.