Technically, there are no limits on how much loot you can bring back into the United States from a trip abroad, but the customs authority does put limits on how much you can bring back for free. This restriction is mainly for taxation purposes: to separate tourists with souvenirs from importers with profit motives.

What and how much you can bring into the United States is controlled by the U.S. Customs office, which basically views you as a small-time importer/exporter. Importers have to pay a governmental duty (tax) on any foreign-made item they bring into the country. However, the customs office realizes that the majority of travelers are merely bringing home items as souvenirs or gifts or for their personal use, and magnanimously allow you to bring in up to $800 worth of souvenirs and a few drops of that Italian wine for free.

Note that this has absolutely nothing to do with the Duty Free Shop at the airport. The "duty," or tax, you are avoiding by shopping at these stores is the local tax on the item (like state sales tax in the United States), not any import duty that may be assessed by the U.S. customs office. All of this is explained on the VAT Refund page.

Well, I Do Declare! Getting Through Customs
In a development so shocking I checked it twice to be sure there wasn't an error, the federal government has actually made it easier to bring your stuff home. As of summer 2003, they doubled the cash value on goods US citizens allowed to take home without paying tax from $400 to $800 per person—so long as you've been out of the country for at least 48 hours and haven't used the exemption in the's past 30 days (rules designed to foil any small import/export sideline an airline crew member might try to get going).