https://www.cbp.gov/trade/basic-import-export/internet-purchases
Pluses: Get seamless delivery. All you have to do is sign for the package when it arrives. In most cases delivery is quick and reliable. When there's a problem, there is a tracking number that can help resolve the matter.
- Courier Shipping: Goods shipped by courier, express, or other commercial service usually are expedited through CBP by a customs broker hired by that commercial service and then delivered seamlessly to your door. Customs brokers are not CBP employees. There are a number of different charges associated with these services, including shipping and handling, the fees charged by the service for clearing the merchandise through CBP, as well as any Customs duty and processing fees that may be owed on your importation.
Pitfalls: Many people have found the various charges and fees levied to be higher than they expected, and sometimes exceed the cost of their purchase(s).
Buyers often have the misunderstanding that when the purchase price includes shipping and handling, all the costs associated with clearing the package through CBP are covered by the seller. They don't realize that brokers fees and CBP duties may be an additional charge that the buyer is responsible for.
Importing Process Paying Duty: The importer is ultimately responsible for paying any duty owed on an import. Determining duty can be very complicated, and while shipping services will often give an estimate for what the duty rate on an item might be, only CBP can make a final determination about what is owed. You should not be misled into thinking your purchase price includes duty because the seller cannot say with absolute certainty what the duty will be. As a rule, a purchase price that includes shipping and handling does not include duty or any costs associated with clearing the goods through CBP. First time importers are often surprised by bills they receive for duty, U.S. Customs and Border Protection merchandise processing fee, and something referred to as "customs fees," which are actually charges for the services of the broker who cleared your goods through CBP.
How you pay duty depends on how your goods were shipped. If your goods were shipped through the International Postal Service, you will need to pay the mail carrier and/or go to your local post office to pay any duty and processing fees owed when your package arrives at that post office. If your goods were sent by a courier service, that service will either bill you for the duty they paid on your behalf or require payment on delivery.
If your goods were sent by freight, there are two possible scenarios for paying duty.
If no arrangements were made to forward the goods to your door, you will need to either clear them through CBP yourself, in which case you will pay duty directly to CBP at the port where your goods arrived. Alternatively, you will need to arrange for a broker to clear your goods. If you hire a broker, they will bill you for their services and any duty they paid on your behalf.
If arrangements were made to forward your goods to you, you will be billed for any duty owed, and for the services of the broker who cleared them through CBP.
Reminder: U.S. Customs and Border Protection holds the importer - YOU - liable for the payment of duty not the seller.