Trips to the grocery store usually end with carts packed full, and a feeling that we have spent too much when the clerk rings up the total.

VIDEO: Savvy Shopper Offers Big Money Tips

But there are quick and easy ways to save money, and one woman is encouraging us to never pay full price for food again.

She said it only takes 15 minutes a week to start saving large amounts of cash.

Stephanie Nelson is known as the coupon mom, and she said she can help everyone become strategic shoppers.

"My mantra is saving on groceries is not about changing the way you eat, it's about changing the way you buy the food you like," said Nelson.

Nelson is a mom who has her own book and Web site that reveals grocery store deals. She recently visited Publix to show how it is done.

She began her experiment by buying one bottle of vegetable oil and getting one free.

"They've actually charged half-price for each item so I can use two coupons and the store will double both coupons," said Nelson.

She ends up paying 62 cents a piece, saving nearly $2 per bottle.

This is a good example that bigger is not always better when shoppers are strategic shopping.

"I always try to get the smallest size because you're paying the lowest price per the item," said Nelson.

Many stores will double coupons, including Publix, which will doubles them up to 50 cents. They also accept coupons from other stores.

"I have two coupons from another store, which I can use at this store. But I can also use a newspaper coupon along with this coupon," said Nelson.

Here's another trick. Don't always use the products pictured as a guide. Read the coupon's fine print.

At checkout, Nelson typically has a coupon for every item. A nearly $103 bill was slashed by $84.53, with the final total coming to $18.28.

Nelson said by using her system, shoppers can save 50 percent off their regular grocery bill.

Learn How You Can Become A Strategic Shopper (pdf)

Visit the Coupon Mom Web Site