Cheap Science Diet at Petsmart!

Ok, this does require a bit of effort.  First, you will need some high value pet food coupons, like the $8 coupons for Science Diet that I posted about here, or the $10 Nutro coupon I posted about here.

You will also need to have the coupon from this past Sunday's newspaper.  Save $5 off any $25 purchase of dog or cat food for Petco. 
This is what I did at Petsmart (yes, they take competitor coupons and their prices are more often than not, cheaper)
3 Science Diet cat food $10.99 each = 32.97
-$5 off $25
-3 $8 Science Diet Printables
Total $3.97
Tax: .33
Cost oop for almost 12 lbs of Science Diet cat food $4.30!

Now of course, this should work similar for the dog food or using the Nutro $10 homemailer that you should be getting in the mail this week(I got mine yesterday)
You can go online to find pricing for the food you might be interested in purchasing, so you know how many coupons you will need.

There were also specially marked cat food bags with $10 coupons in them for Petsmart.  These bags were $30.99 so if you purchased one, it would look like this:
1 @ $30.99 - $5/25 - $8 = 17.99 but get $10 coupon for future order = $7.99.  This way comes out slightly cheaper per lb and would work for those with limited numbers of high value coupons.  (I am not 100% sure what the $10 coupon in the bag is as the description seems vague, so I opted for the cheaper up front out of pocket option)