The U.S. Customs motto is: "Know before you go." That's good advice. You should find out what items are allowed and what the duty (import tax) will be on items before you board cruise ships or fly to distant lands. Think of the disappointment when you find out that what you bought won't be allowed into the U.S., or that the bargain price you paid for an item turns out to be a small fraction of the duty you have to pay.
Cruise ships or airplane passengers who arrive in the U.S. are expected to submit a list of any goods they acquired while they were out of the country. That includes items you purchased or received as gifts, and even items that you inherited. Items bought in duty-free shops aboard cruise ships or other carriers should be declared, including those that you might be expecting to give as gifts.
Note that any computers or other electronics that you took with you can be taxed as imports if you can't prove that you bought them in the U.S., so take along sales receipts. Better yet, register such items with customs officials before you leave the U.S.
You're entitled to a duty-free exemption that varies from $200 to $1,200, depending on the country you visited. You're also allowed to combine your exemption with your spouse's if you wish. You can get additional exemptions for tobacco products and alcohol if you're of legal age to purchase them. All items you buy must be intended for personal use or as gifts.
Any item whose value exceeds your exemption will be taxed. For example, liquor that exceeds the one-liter exemption will be taxed at the standard two percent rate.
If you visit a duty-free shop, you can often get a great deal on perfume, tobacco products, jewelry and alcoholic beverages, but don't make the mistake of thinking that items acquired in duty-free shops don't count towards your exemptions.
Packing and shipping your purchases can lighten your luggage but it's not necessarily a cheaper alternative. The international shipping cost may be high. Duty-free exemptions apply only to goods you actually carry with you into the U.S.
Some items simply can't be brought into the U.S. at any cost, and you may forfeit them altogether if you ignore import laws. You might also get stuck with the cost of exporting them! Remember, international shipping costs can be high. Examples of prohibited items include:
The list of prohibited items is long. In general, remember that animals, food and plants are almost always restricted. Also, you won't be allowed to import items from Cuba and other embargoed countries.
If you're an enthusiastic shopper, stick to clothing and normal tourist souvenirs. Don't exceed your personal exemption and use international shipping options with those limits in mind. Declare everything you're planning to bring into the U.S. Sneaking items in isn't a game — it's breaking the law.
Pack your souvenirs and acquisitions together so that you can show them to customs officials. Above all, never agree to take back items that a stranger gives you. You could be putting yourself and many others in danger.