For most of us, an important part of our winter vacation is stopping by the airport's duty free store to grab some cheap chocolate or liquor.

While every country is a little different, the gimmick behind these stores is that you save money because everything in them is tax-free. But is that true?

While there are some exceptions, the truth is that you can get almost everything these stores sell much cheaper somewhere else.

The only thing that's always safe to buy at these shops is cigarettes. Because their prices are almost 100% tax, you're guaranteed to save a lot of money. You may think this is also true about alcohol, but it's not.

There are lots of small costs that are easy to miss, which is how duty free shops trick you out of your money. For one thing, if you're shopping in another country the exchange rates can raise the price. Also, stores will simply raise prices on booze. Sure, you're not paying taxes, but it's still not a good deal.

More expensive products like electronics, perfumes and cosmetics are even worse. The deals are almost never in your favor, and if you spend too much by accident you can end up paying taxes!

Yes, that's right, there's a limit to how much duty free product you can buy, depending on how long your trip is and where you go. So you might avoid taxes at the cash register, then pay them at the customs counter (which feels way worse).

There is an easy way to actually save money while shopping on your vacation: most countries let you avoid paying local taxes on big purchases anyways. All you usually have to do is prove you're a foreigner, so be sure to ask before you splurge on that diamond necklace.

If you absolutely need to buy some last minute candy before your flight, the duty free store is your friend. Otherwise, stay far away from it!