For shoppers like Deborah Walker, the sound of a receipt printing from a cash register is as good as the sound of money printing.

"It's been very beneficial to keep receipts," she said.

Walker uses receipts to put cash in her pocket.  She does it by taking the survey at the bottom of a receipt.  In one example, she earned $25 towards a future car rental.  

And receipt coupons for pet products help her save cash she uses towards food for her pooches, nights on the town, or new clothes.

"Consumers can easily save about a hundred dollars a month just by looking at the receipts in a new way, and looking for hidden cash on them," explained financial expert Denise Winston.

Winston has her own cache of receipts, and says coupons and discounts are just the beginning.  Some receipts even offer "free stuff" for giving a business feedback.   

But statistics show, as many of 60 percent of people don't participate.  And only about 1 percent of the coupons on the back of receipts are redeemed.   

Just by cashing in on those cash register printouts Winston estimates Americans could save billions of dollars each year! 

"They're really cash not trash," she said.

It's a lesson Winston has learned over and over.   When a watch she bought went kaput during the warranty period, having the receipt was critical to getting the repair work done.  The manufacturer fixed it, saving her $300 she would have spent to replace it!  

And a wireless router went on sale soon after Winston purchased it. Her receipt helped her make money with a price match guarantee.

"All I had to do was take my receipt in, um and then they gave me the 40 bucks back," said Winston.

Industry experts say if you use a loyalty card at a retailer you will get more coupons, and more targeted coupons.   If you don't, you could be losing out on savings.

"Some of the money that you may leave on the table is going to be lost because they're not gonna have that transactional data and they're not going to be able to offer you those rich, targeted receipts," said Mark Johnson with the Loyalty Marketer's Association.

So, how do you avoid becoming a receipt hoarder?   Winston says save them in a simple envelope or file folder.  Toss coupons and surveys that have expired, but save receipts for expensive purchases.

"It can be as basic or as complex as you want, but the key is start to do it right now," said Winston.

Walker says "doubling down" at the store helps her save even more money!

"I like to play the system, look for the sale, and use your coupon at the same time," she said.

Walker says saved receipts have helped her prove what she paid for an item if she sells it at a yard sale.  And, if you buy an item that offers a rebate, receipts are critical to cashing in. 

Another reason to check your receipts: Some stores are using them to give you important information about recalled products you may have purchased.   

Finally, if you're worried about your privacy, you can opt out of loyalty rewards programs.