With the weekly shop taking a bigger bite out of your budget every month - it’s time to start getting savvy at the supermarket.

And, while some smart shoppers use coupons to shave pennies off their bill, there are certain items that you should be skipping entirely.

Consumer savings expert Andrea Woroch told Mental Floss that buying some products at the supermarket could actually end up costing you a lot more with mark-ups as high as 100 per cent.

So, what items should you be avoiding?

More often than not, we end up splurging on items for the sake of convenience with things like pre-prepared fruit and vegetables high on the list.

From diced carrots, sliced pineapple and cubed butternut squash, you probably already know that these packets are going to cost you more but do you know just how much?

It turns out that these pre-chopped items will cost you a whopping 40 per cent extra than if you were to grab some fresh produce at a local market. It might save you five minutes but you’re paying a big difference.

The same goes for pre-packaged meat too. Buying ready-made burgers or kebabs could actually cost you anywhere between 60 and 300 per cent more than buying the meat in its whole form.

How Brexit affected Britain's favourite foods from Weetabix to Marmite Show all 8 1 /8 How Brexit affected Britain's favourite foods from Weetabix to Marmite How Brexit affected Britain's favourite foods from Weetabix to Marmite Weetabix Chief executive of Weetabix Giles Turrell has warned that the price of one of the nation’s favourite breakfast are likely to go up this year by low-single digits in percentage terms. Reuters How Brexit affected Britain's favourite foods from Weetabix to Marmite Nescafé The cost of a 100g jar of Nescafé Original at Sainsbury’s has gone up 40p from £2.75 to £3.15 – a 14 per cent rise—since the Brexit vote. PA How Brexit affected Britain's favourite foods from Weetabix to Marmite Freddo When contacted by The Independent this month, a Mondelez spokesperson declined to discuss specific brands but confirmed that there would be "selective" price increases across its range despite the American multi-national confectionery giant reporting profits of $548m (£450m) in its last three-month financial period. Mondelez, which bought Cadbury in 2010, said rising commodity costs combined with the slump in the value of the pound had made its products more expensive to make. Cadbury How Brexit affected Britain's favourite foods from Weetabix to Marmite Mr Kipling cakes Premier Foods, the maker of Mr Kipling and Bisto gravy, said that it was considering price rises on a case-by-case basis Reuters How Brexit affected Britain's favourite foods from Weetabix to Marmite Walkers Crisps Walkers, owned by US giant PepsiCo, said "the weakened value of the pound" is affecting the import cost of some of its materials. A Walkers spokesman told the Press Association that a 32g standard bag was set to increase from 50p to 55p, and the larger grab bag from 75p to 80p. Getty How Brexit affected Britain's favourite foods from Weetabix to Marmite Marmite Tesco removed Marmite and other Unilever household brand from its website last October, after the manufacturer tried to raise its prices by about 10 per cent owing to sterling’s slump. Tesco and Unilever resolved their argument, but the price of Marmite has increased in UK supermarkets with the grocer reporting a 250g jar of Marmite will now cost Morrisons’ customers £2.64 - an increase of 12.5 per cent. Rex How Brexit affected Britain's favourite foods from Weetabix to Marmite Toblerone Toblerone came under fire in November after it increased the space between the distinctive triangles of its bars. Mondelez International, the company which makes the product, said the change was made due to price rises in recent months. Pixabay How Brexit affected Britain's favourite foods from Weetabix to Marmite Maltesers Maltesers, billed as the “lighter way to enjoy chocolate”, have also shrunk in size. Mars, which owns the brand, has reduced its pouch weight by 15 per cent. Mars said rising costs mean it had to make the unenviable decision between increasing its prices or reducing the weight of its Malteser packs. iStockphoto

According to Andrea, spices also have an exorbitant mark up of nearly 100 per cent. Instead, she recommends buying them at a natural foods store where they tend to be cheaper.

Single-serving portions of crisps can trick you too, typically running 30 per cent more expensive than a big bag of the same product.

It’s not just food that’s to blame here though, as we scour the aisles we’re often tempted to pick up ‘essentials’ we could get elsewhere at a fraction of the price.

Batteries, for instance, are what Andrea deems a ‘classic impulse buy’ which is why you usually find them places near the till points; a place you’re less likely to think about making a saving.

Instead, resist the temptation to chuck them in your basket though and buy in bulk online.

Lastly, you’re going to want to avoid buying any personal care products like deodorant, shampoo or cosmetics as this could end up costing you an unnecessary 30 per cent more.