I found this in Redbook Magazine Sept '07, page 48C regarding lunch/snacks

One easy way to save is to skip individual size packages and create your own single portions. A family of 4 can save up to $2,000 a year by purchasing a box of 100 count sandwich bags to fill with pretzels and chips, and by swapping single-serving juice boxes for a reusable plastic drink carrier. Apply these tacts to your meals as well: bringing lunch from home will save you up to $1,000 a year. And if you swap that a.m. latte for a cup of joe at home, you'll be $1,140 richer by next September.