Duty free stores are often located in international airports, and on the borders of many countries. If you are travelling internationally, you will benefit from the tax free items you can purchase at Duty Free Stores.
Maximizing Cost
If you intend to find the best "percentage off retail" price for an item at a duty free store, you should purchase products that offer a very high duty rate, like liquor and cigarettes. Many duty free stores will offer these items in bulk, maximizing cost and allowing you to benefit from the lack of tax on them. Many stores offer high end designer brands at discounted prices. If you are focused on overall dollar savings, these high end items are where you're going to find the biggest discounts.
Convenience
Comparing duty free shops located in cities to duty free stores located in airports, the biggest difference is the overall convenience of the airport shops. While many shops offer high priced items, the benefit to buying them in the airport is that you may use currency that will decrease in value when you leave the country you're currently in. Even if the currency does not depreciate, the conversion rate you will be charged will definitely make it worth it to purchase the item in the airport instead of in a store.
Requirements for Duty Free Shoppers
As a rule, to take advantage of duty free shopping, you must leave the country within 48 hours of your purchase. This is why most duty free stores are located in international airports and shops. You must take the items you have purchased with you to your next destination. You're not allowed to re-enter the country with the items you have previously purchased there.
Duty Free International
Many European countries offer fewer duty free benefits than other countries, because of the European Economic Union, which handles cross border taxation. Some countries that are ideal for duty free shopping include Australia, Mexico and Argentina.
Duty Free Limits
Each country imposes its own individual limits on how many duty free items can be purchased at one time. When re-entering the US, a limit of $800 worth of duty free items can be brought into the country. Certain ounce limits with respect to alcohol and cigarettes are often enforced on travelers. If you go over the allotted limit, you must announce it when going through customs, and you may be charged additional fees. The way to avoid these additional fees is to make sure that you're aware of the legal duty free amounts that you can bring into your native country.
Additional Benefits
Additional benefits to shopping duty free include access to high end sunglasses, sports wear, toys, books and perfumery. All of these items will be tax free and discounted, because you will be leaving the country within 48 hours of your purchase.