For most of us, receipts are simply one more bit of clutter in your handbag or pocket - at most, you might hang on to them in case a product breaks down.
But for some people, these little scraps of paper are a source of cash in themselves. Canny shoppers are taking good care of their receipts - and even other people's - to make themselves a bob or two.
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Using an app called Receipt Hog, you can scan receipts from supermarkets and high street stores and upload them for cashback, earning 'coins' that you can then withdraw using PayPal.
You can upload up to 20 receipts a week, and there are also rewards for, for example, connecting through Facebook or completing questionnaires.
"For the sake of a minute taking a photo and clicking upload, it is definitely worth it," says Ricky Willis, otherwise known as Skint Dad.
"This app will not make you a fortune but it will add a few quid to your back pocket!"
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Old receipts are also useful for cashback, thanks to price guarantees. Asda's price guarantee website, for example, allows you to print out coupons just by scanning in receipts once you get home.
Not only can you use them on price guarantee websites and apps like Receipt Hog, there's a fair chance there'll be money off vouchers thrown away with them too.
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Last year, we reported on Cal Holder, a 40-year-old from Birmingham, who says she made £960 from wombling alone the year before.
And more recently, thrifty shopper Anushka Fernando revealed that wombling had netted her her entire Christmas dinner for free.
"When I was shopping in my local Asda I began to notice there were so many discarded receipts lying around in and around the store," she said. "Once you start looking, they are everywhere - on the floor, outside, and in trolleys!"