Ideally, you would use (3) $1/3 GM coupons available online at smart source.
You would purchase 10 boxes of Cocoa Puffs, Cookie Crisp, or one of several other cereals on sale for 2/$4. Total cost $20.00 less the three $1 coupons= $17.00 for 10 boxes of cereal or $1.70 per box. But, the deal really sweetens when you get an instant savings of an additional $5.00 discount bringing your total to $12.00 for 10 boxes of cereal or $1.20 per box.
I had to mix and match my cereal purchase because I did not have enough of any one type coupon to fully maximize this deal. I used (3) $1/2 Chex Cereals which were on sale for 2/$5.00 and (1) $1/3 Any GM Cereal. My total came to $23.00 for 10 boxes of cereal. Less $4.00 in coupons= $19.00, Less $5.00 instant savings for buying 10 boxes= $14.00 for 10 boxes or $1.40 each box.
I also purchased Cains Dill Relish using a .55/1 coupon (which doubled to $1.10) for a profit of .13 cents. Additionally I needed butter and used a .50/1 Land-O-Lakes coupon (which doubled) to cost a total of $1.68 for the tub.
Catalina perk: I earned a coupon for $2/5 GM cereals to use on my next visit and I earned 35 bonus box tops for my kids' school's PTG group. I register the codes online for free. It takes mere minutes to do and I earn money towards field trips and other extras for my local school by buying things I already planned to purchase. Today's trip added another $3.50 donation.