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ABC News’ Becky Worley reports:

Every year there are 15,000 new food items added to grocery shelves. And thousands of them are pre-made versions of things people used to make at home. So when does it make sense to buy it and when is it better to make it?

Jennifer Reese, a California mother and author of “Make the Bread, Buy the Butter,” went on a year-long quest to figure that out.

Reese started seriously looking into the issue when she was laid off from her job and sought to save money on groceries.

“I’d rather make bread than run to the supermarket,” she said. “And it turns out to be a couple of dollars per loaf cheaper to make it than to buy it. ”

That’s right. According to Reese’s research, it costs her $1 to make a loaf of bread, than to spend $4.39 to buy it from the grocery store.

Here are the results of her research for other popular grocery items.

Maybe you should consider making these:

Hot dog buns: Homemade, 17 cents each; store bought, 37 cents each

Hummus: Homemade (1 cup), 85 cents; store-bought, $3.10

Guacamole: Homemade (1 cup), $1.50; store-bought, $4.50

Frosting: Homemade (1 cup), $1; store-bought, $2.

Vanilla extract: Homemade (one ounce), 50 cents; store-bought, $4.50

Croutons: Homemade, free! store-bought, $2.30.

And you might want to buy these:

Sure. These may be cheaper homemade, but Reese thinks the time and hassle involved make store-bought preferable.

Lemonade: Cost isn’t a major factor, but the hassle makes buying preferable, Reese believes.

Potato chips: Homemade, 80 cents; store-bought, $1.30

Rotisserie chicken: Homemade, $3.40 per pound; store-bought, $3.60 per pound.