Around 40 percent of the food we have in the United States ends up in the trash -- primarily food that's gone bad at home. One way to cut back on waste is to buy exactly what you need from the grocery store when you're trying a recipe at home. If a recipe calls for two potatoes, don't buy a whole bag. Instead, look at loose produce and get what you need. Use the bulk bins for spices, grains, nuts, seeds and flour. Approximate what you need and avoid pre-packaged bags and boxes, especially if they aren't commonly used ingredients. You'll cut back on waste and save a significant amount of money, too.