Pam Brossman, 50, of New South Wales was a former customer of Coles and IGA, but switched almost immediately to German chain Aldi when it first launched in her hometown of Mosman because it was “so much better value”.

She has shopped at the bargain supermarket ever since, swearing never to return to the bigger stores.

“Aldi has much better variety, and I can do pretty much everything in the one spot without having to go anywhere else,” Ms Brossman told The New Daily.

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“If I go shop at IGA here in Mosman, everything is three times what I pay at Aldi.

“Price-wise, I’m more than happy.”

Ms Brossman has made the right choice, if new data is correct. On average, Aldi has the nation’s cheapest groceries, consumer advocacy group CHOICE has found.

A basket of 31 common big-brand items would cost almost $74 more at Coles and $84 more at Woolworths than a basket of private label equivalents at Aldi, CHOICE estimated.

The consumer group sent undercover shoppers to 32 Coles stores, 32 Woolworths stores and 18 Aldi stores in wealthier and poorer areas across Australia to calculate the average prices.

Even with specials included, a Woolworths basket cost an average of $172.16, compared to $162.56 at Coles and $87.57 at Aldi.

“By foregoing leading brands at the big two supermarkets and heading to Aldi, you can save about 50 per cent off your weekly grocery bill,” said CHOICE spokesman Tom Godfrey.

‘We’ll do better’

Parents and grandparents are not the only consumers enamoured with the cut-price supermarket, with at least one young Aussie “convert”.

“I simply can’t face the idea of doing a big shop at Coles anymore,” Samantha Lenkic, 25, from Melbourne told The New Daily.

Not every item is available at Aldi, forcing Ms Lenkic to shop occasionally at the bigger stores, much to her annoyance.

“It physically hurts to do so because the cost of a small bag of groceries would fill up half my trolley at Aldi,” she said.

Coles responded to the price comparison by highlighting its recent success in driving down prices, and pledging even lower prices.

“Coles has been unrelenting in driving down prices for our customers over the past six years, and that will not change,” a spokesperson told The New Daily.

“Compared to six years ago, an average Australian household can save an average of $570 a year by shopping at Coles and we are absolutely committed to further reducing prices for our customers so they can save more at our supermarkets.”

Woolworths also pledged to “do even better” in future, and criticised the survey’s methods.

“Comparing a handful of products is rarely an accurate way to judge prices across a whole weekly shop,” a spokesperson said.

“Products like our Homebrand and Select products offer great value and quality and we are looking to do even better in this area in the future.”

How to save even more

Consumers who prefer one of the bigger supermarket chains can still find bargains.

For example, a basket of homebrand goods at Coles was $48 cheaper than a basket of equivalent big-brand items at the same supermarket.

“If Aldi’s no-frills experience is not your thing, but lowest price is a priority, you can still save 35 per cent at Coles and 33 per cent at Woolworths by swapping leading brands for the chains’ private label equivalents,” CHOICE spokesman Tom Godfrey said.

The growth of private label items will continue, to the benefit of consumers, a spokesman for the supermarket industry predicted.

“That’s certainly a trend,” Australian Food and Grocery Council spokesman James Mathews told The New Daily.

“Coles and Woolworths are recognising that the future of brands and their future are also linked and that consumers are looking at, yes, price, but they’re also wanting choice and variety as well,” Mr Mathews said.

“Our view would be that the long-term interest of the consumer is best met when there is a wide range of choice.

“Choice creates a proper market.”

The items CHOICE compared