"People that just sort of haphazardly clip their coupons and stroll through the aisle, they're going to save a little, but they're not going to make a huge difference at their bottom line on their grocery budget," said Nathan Engels, who has earned the nickname "Mr. Coupon" for his strategic use of coupons to save.
Engels runs a Web site, "We Use Coupons," that sees the kind of traffic most grocery stores can only covet.
The site got its name from the response Engels and his wife would give when people asked them how they saved so much money at the store.
The 28-year-old from Villa Hills, Ky., spends almost no money on groceries -- and sometimes walks out with a credit. His garage is filled with astonishing quantities of Jell-O, freezers full of veggies, and shelves of shampoo and toiler paper -- all booty from his extreme couponing trips.
"The last time I purchased toilet paper at the store was in 2007," he said, boasting that a three-year supply cost him $30.
To learn the secrets of the couponing world, "Nightline" visited Engels and Jill Cataldo, also known as "The Coupon Queen," who teaches classes in Chicago and writes a nationally syndicated column about coupons.
"Our weekly grocery bills right now for our family of five are between $40 and $60," she said. "And that's everything, pets, child and diapers, everything."
Watch the story on "Nightline" tonight at 11:35 p.m. ET
The Internet has made this new breed of couponing possible. Engels and Cataldo share information on deals on their Web Sites, connecting thrifty shoppers in a nationwide network of supermarket intelligence.
The success of their Web sites has made Cataldo and Engels celebrities of sorts in their communities.
"I can't really go the grocery store too often without being recognized here in Chicago anymore," Cataldo said.
"Nightline" challenged Cataldo and Engels to put their couponing skills to the test to see who could make $50 go further towards their weekly grocery bill.
How to Save at the Grocery Store
Cataldo headed to her favorite store, Jewel-Osco and Engels didn't waste any time hitting up Kroger.
Weaving through the supermarket aisles, the experts shared their tips and tricks on how to save big.
Tip #1: Get Paid to Shop
By clipping coupons and looking for special promotions, Engels actually gets manufacturers to pay him to buy their product.
"It's called an overage. It'll be right off my bill at the end," he said, explaining what happens when the coupon's value exceeds the actual price of the product.
The store was also running a special promotion -- buy eight cans of tuna, get $4 off -- so Engels actually turned a profit.
"We don't care about the tuna in this instance because we're getting it for free and then actually we're going to make a little money," he said while loading tuna into his cart.
Cataldo's first stop was the customer service desk. Always on top of a deal, she heard about a sale on diapers, so she called the store in advance to have them save her a box.
"This is the size my little guy wears, so I said, 'Hey, if you have one left, can you hold it for me,' and they're usually great about that," she said.
With the sale and a coupon, the price was about 7.5 cents a diaper.
Heading over to the produce aisle, Cataldo shared her first tip: don't fall for the myth that coupons are only for junk food.
Tip #2: Use Coupons for Organic Food
Cataldo brought a coupon for organic broccoli, which was on sale for less than $1.50.
Tip #3: Get a Rain Check
If a store is all out of something you have a coupon for, shoppers can get a rain check.
"Let's say this was on sale," he said, pointing to a box of cereal, "And there was none left and someone had wiped it out. What we do is go to the service check and get a rain check. What the rain check does is it extends the sale price of the item for 30 days. So you can still go to the store and ...get as many as you want."
Tip #4: Don't Throw Catalina Coupons Away
Another way Cataldo saves is with Catalina coupons -- the kind that print out of a special machine at the register. They're just like cash, she said.
"If it seems like I'm buying a lot, it's because I am," she said. "While it is on sale for $1.50 a box, there's another Catalina deal on this when you buy five you're going to get $4 back and another one you're going to get $2 back, so that's six back with coupons, it's going to cost me less than six. So I'm actually going to get paid to take this home today. And why wouldn't you take home free cereal that you like?"
Super Couponers' Techniques
By the end of the challenge, our shoppers' distinct styles were clear. Although Cataldo said she will always take something home if it's free, she said she tries to only buy what her family will use.
She seemed to have a different philosophy than Engels, who was willing to take home as much stuff as humanly possible...as long as he paid little or nothing for it. He purchased what looked like a lifetime supply of air freshener.
Cataldo shops so she's stocked for just three months.
"I'm going to buy 12 weeks' worth because I know about three months from now, prices are going to dip again," she said. "And we're going to go in and do it again. And of course we use coupons and cut it even more."
Engels buys enough stuff to last a year. "The strategic way of doing this is that I don't have to buy [frozen veggies] every week like most people do," he said.
While it may seem like a crazy game of clipping and saving, coupons helped Engels get out of debt. Now, they're almost completely debt free.
"When my wife and I got married in 2007 we started to look at our finances and we realized we had $17,000 in credit card debt alone. We said, 'We need to do something different. We need to start saving, we need to pick up more hours at work.' So what we did is we started to do everything. We worked harder and we started to look at coupons," Engels said.
Both carts were full when they reached the finish line. The results?
Pre-coupons, Jill Cataldo rang in at $118.84. After all her coupons were scanned, her groceries came to a grand total of $50.61.
Plus, she scored $20 worth of Catalina coupons to use on her next shopping trip.
A clever combination of coupons left Nathan Engels with $19 to spare. He said he spent $30 on groceries that retail for about $500.