A Woolworths shopper has warned Australians who almost overpay for a popular item to always double-check the prices of their groceries.

When the shopper was at the self-serve checkout Sunday, the price of a package of pitted prunes was $7.50, even though it was marked $4.90 on the shelf.

But the mistake exposed Woolworths’ often forgotten policy.

‘Decided to get these for free because the staff was hanging around and not believing me,’ the customer wrote on Reddit.

‘They said the price went up but someone didn’t change the label.’

Items scanned at a price higher than the in-store ticket price will be given free to shoppers in accordance with the supermarket’s policies.

Social media users also claimed that they received free profits due to pricing errors.

‘Yes, I got a few items for free because they scanned the wrong price,’ one wrote.

A customer was charged almost 50 per cent more than the ticket price for prunes at Woolworths

They saw on the shelf that the price was set at $4.90, and after alerting the staff, they received the prunes for free

‘Most people probably won’t notice, but I’m sure some missed it.’

“If you have slots on your phone, go to the online chat, tell them what happened and you should get a full refund and the store will be notified that it did not comply with policy,” another said.

‘Apparently, even though some things have the wrong name (and hence different pricing), you get it for free,’ objected another.

‘I got a free bunch of flowers because they were labeled with a different type of flower!’

Other commenters focused more on the shocking price increase for the popular dried fruit product.

‘Of all things, the price of prunes should be regular,’ said one.

“The worst part of this post is knowing that a 500 gram pack of pitted prunes went up $2.60,” another wrote.

One said: ‘A 50 per cent price increase is awful.’

Daily Mail Australia has contacted Woolworths for comment.