>> #0: will my buyer have to pay any extra cost for customs while receiving?
As said above, the importer is responsible for any import duty and any additional charges imposed by the importing country (unless you agree otherwise in advance -unlikely in a one-off personal sale). To avoid misunderstandings, it is always best to put a warning notice on your international auctions such as:
"Any Import duty and any other related taxes are to be paid by the buyer".
www.sloanefox.freeserve.co.uk/imptaxwng.htm
The US has quite a high import duty allowance threshold of $US 200. You, and others reading this, might find these links helpful:
> US Import Duty, Allowances, Exemption, Internet Purchases, US Customs & Border Protection (CBP):
www.cbp.gov/xp/cgov/trade/internet_purchases.xml
>> What is my US import exemption? US Residents and Non-Residents - Gifts - Duty Free - Alcohol - Tobacco - NAFTA - GSP etc.:
cbp.gov/customs/answers/detail/a_id/454
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