Supermarket Sleuths: Can customers really save at Costco when it comes to pantry staples?

Comparing costs between Costco products and major supermarkets can prove difficult, but I've given it a crack for this week's Supermarket Sleuths.

The difficulty lies in the fact Costco focuses on bulk purchases, whereas Coles and Woolworths tend to sell grocery items in smaller packaging.

The further difficulty is all the fun and exciting novelty products they sell that simply can't be compared!

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Giant choc chip cookies, fresh lemonade and two giant pizzas are just a few of the unplanned items that landed in my enormous trolley during my most recent visit – and a $6.99 rotisserie chicken.

The best way to compare the cost of Costco products to those at the majors is to go through each item one by one based on their per unit price.

This is exactly what I've done this week, focusing on some of the more popular bulk purchases families have come to rely on.

Let's start with bottles of water, with Costco's bulk purchase 30 600ml bottles proving popular every time I am there.

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Breaking it down to the per unit price, one bottle of 600ml water at Costco costs customers $0.36.

Coles sells 24 packs of 600ml water bottles for $9.90 and the price is, on average, $0.41 per bottle. Woolworths water bottle packs are $10.00, just slightly more, rounding up close to $0.42.

This leaves Costco as the winner in this category.

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Next up is a popular purchase for back-to-school, Golden Circle poppers.

At Coles and Woolworths, a six-pack of these will cost customers $4.00 on sale. At Costco, the cost per six pack works out to be $3.24.

But you do need to commit to a box of four six packs, which is perfectly fine in my household of mobile juice lovers.

Now, to a pantry mainstay: tinned diced tomatoes and passata.

Costco is selling 12 packs of tinned diced tomatoes for $11.99, which works out to be $0.99 each.

Coles and Woolworths both offer much cheaper versions, but the only way to fairly compare this cost is to go for the lowest priced Italian diced tomatoes.

Costco's brand is Sole Natura. The most affordable Italian diced tomatoes at Coles are their Cucina range at $1.40 per tin, while Woolworths sells Annalisa diced tomatoes for $1.35.

That leaves Costco the clear winner when it comes to tinned diced tomatoes, and I can't tell you how calm it makes me knowing I have 12 tins in my pantry. I seriously use them for everything.

Next up, Mutti Passata, which is the best by far, as far as I am concerned.

Costco is selling six packs of Mutti Passata in 700 gram jars for $19.99, which works out to be $3.33 per bottle.

Coles also sells Mutti Passata for $4.80, which is much pricier than Coscto. Woolies is closer to the wholesale retailer's price at $3.80 per 700 gram bottle.

Coke No Sugar is another staple in my home. My teenager smashes a 1.25 litre bottle one sitting, so I deliberately 'run out' of it to reduce how much he consumes.

Still, I was delighted to see it on sale at Costco in packs of six 1.25 litre bottles for $11.99, meaning customers pay $1.99 per bottle.

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Coles has a sale on at the moment for Coke No Sugar, two for $5.20, making the per unit price $2.60 each.

But it was Woolworths that was once again closest to Costco's price, selling them for $2.00 each.

Raw sugar is the best sugar for tea and coffee by far, and seeing Sunshine Raw Sugar in a three kilo bag was thrilling. It cost just $4.29 at Costco, meaning customers pay $1.43 per kilo.

Coles and Woolworths matched each other's price when it came to raw sugar, with Coles selling two kilo bags for $3.20, meaning customers pay $1.60 per kilo.

Woolworths sells three kilo bags for $4.80, which also works out to be $1.60 per kilo as well.

Go Costco!

People were making a beeline for eggs at Costco due to the current egg shortage, which sees Coles and Woolworths running out completely from time to time.

At Costco we managed to nab a 30-pack of cage free eggs for $12.69 and this means we are paying $0.43 per egg.

Coles is also selling cage free eggs for $7.90 for a pack of 18, which worked out to be the same price as Costco.

Woolworths didn't have any egg stock listed on its website on the date of publication but did list some free range eggs as "in store only". When they do have them in stock, they tend to be the same price as Costco and Coles.

Pork is the "other white meat", as the old ad tells us. I must say, I do love a pork chop from time to time and we are always looking for different meats we can barbeque.

At Costco we picked up a 1.496 kilo pack of pork loin chops for $19.43, which works out to be $12.99 a kilo. This turned out to be an incredible price.

The most affordable pork loin chops at Coles and Woolies are on sale for $19.00 so run, don't walk to Costco for that.

Dilmah Ceylon teabags do big business. They are the best.

I usually buy the Extra Strong variety but seeing as my son has taken to using two teabags per cup, I'm happy with Costco's pack of 300 teabags at $13.99 which, when broken down, works out to be $4.66 per 100 teabags.

This beats both of the major supermarkets' cheapest Dilmah offering.

Coles is selling them at $14.00 for 200 teabags, leaving customers paying $6.00 per 100 teabags.

Woolworths is the closest with Dilmah Ceylon on sale this week at $5.00 per 100 bags, but that is not their standard price.

For those who have forgotten how delightful fresh pears are, they are available in abundance at the moment.

Costco is selling two kilo packs of snacking pears for $8.99, which works out to be $4.49.

This, however, is not the cheapest price. I compared these to both Coles and Woolworths most affordable pears, their imperfects range. Coles has their I'm Perfect pears on sale for $4.90 but Woolworths beats them both by far, selling their Odd Bunch pears for $2.30 per kilo.

Now, who is the winner overall when it comes to these items base on per unit prices?

Costco: $33.91

Coles: $45.14

Woolworths: $39.90

That leaves Costco the winner, followed by Woolworths and then Coles.

It is worth noting Costco prices are their regular prices, and many of the Coles and Woolworths items were based on their sale prices, not their regular prices.

** Prices are subject to the date of publication, region and availability.

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