While I was at Walgreens, I spotted shelf tag coupons next to the pepsi products!  This week the 2 liters are on sale three for $4.00.  If you find these coupons at your store, you can get the following deal:

Pepsi Products, 2 liter $1.33, On Sale thru 10/1
When you buy 3
Use $1.00/4 Pepsi or Mountain Dew, 2 liter from shelf tag
Final Price:  $1.08 each when you buy 4