The duty free mistakes that could either cost you money or hold up your flight

KILLING time in the duty free shops is one of the most popular ways to while away the hours at airports.

While there are savings to be had, with no tax or duty to be paid on certain items, there are some pitfalls that may cost passengers both time and money.

Therefore it's important to know exactly what can and cannot be gained from a trip to the duty free zone - and how you can get held up.

Firstly, it's good to know which items are normally cheaper in duty free, and which will end up costing you more.

Alcohol and cigarettes are usually always cheaper and the main items travellers stock up on when passing through the airport.

However, things like snacks, medicine and electronics are often more expensive.

Airports will often put those prices up to try and make the most of their captive audience, who have no other options once inside the terminal.

Narendra Khatri, principal of Insubuy and a frequent air traveller told : "Try to avoid buying snacks, over-the-counter medication and last-minute travel accessories like headphones and neck pillows at the duty-free shop if you can."

Another item that needlessly costs passengers at the airport is water, which can cost a fortune from duty free shops.

Former flight attendant Arina Bloom told  how passengers can get water in airports for free instead.

She said: "You can't take liquids through security, but no one says you can't take an empty bottle.

"Most airports are full of water fountains, and many have a special pump to refill bottles quickly.

"To keep your bottle full during the flight, just ask your flight attendant for a refill. If you're lucky, they may even put ice in it."

As well as overpaying for things, passengers can get delayed at duty free too.

Therefore, they should know exactly what to expect from a trip to the airport shops.

Stuff also advise passengers that "you probably only have a limited time to shop" and that comparing prices for items could eat up valuable time.

Travellers should also always have their passport and boarding pass on hand, as they will sometimes be asked for them by staff in the duty free shops.

This is so that the airport staff know where passengers are travelling to. If you're flying outside of the European Union, the shops can claim back the VAT on your purchases, and save themselves some money.

The HMRC website says: "Duty-free shops can sell goods where the excise, customs duty or VAT has been suspended, usually alcohol and tobacco.

"Sales in duty-free shops are tightly controlled and HMRC requires these outlets to know where the passenger is travelling to before completing a sale.”

Meanwhile, this mum revealed the big errors that parents make when travelling with children.

And an easy plane ticket mistake could end up costing you money.