While cooking for ourselves is definitely cheaper than eating out, we're probably still not saving as much as we could. Because, truth be told, we don't always make the most of the groceries we buy. Sometimes we end up with a bunch of leftover ingredients from a one-off recipe, or we have to go to the supermarket multiple times during the week in order to get everything we need.That changes now. With a little preparation, and creative reuse of ingredients, you can whip up three effortless meals that only require one trip to the store. Simply buy this list of 12 ingredients at your local supermarket on Sunday or Monday, and that one bag of food will feed you three healthy and delicious dinners throughout the week. Plus, the whole trip will only cost you approximately $20, which means each of the following dishes is only $5 a serving or less.Note: We used Peapod to determine the cost of our grocery list, but prices will vary depending on where you shop and how careful you are when it comes to certain ingredients on the list. Buy generic, on sale, and in bulk as much as possible and you should be able to stay within the $20 range. A secondary trial run at ShopRite came closer to $22. (The $20 budget doesn't include tax.)