So I bought three books from Amazon.com. I paid $332.96 including about $40 for S&H. To my surprise, in the notification form sent to me by the Indonesian Postal Service, I had to pay an extra Rp432,852 -- that's almost $50. I complained.
First, I visited the Indonesian Postal Service. A staff explained to me that the 50 bucks were charged by the Indonesian Directorate General of Customs and Excise. The Postal Service only shared part of the S&H with the US Postal Service.
So I went to the Customs and Excise Office. The gentleman there nicely explained to me that for any personal purchase from abroad with value of $50 or more, the State would charge either 1) Import tax, and/or 2) Excise, and/or 3) Value-added tax, and/or 4) Sales tax, 5) Luxurious good tax, and/or 6) Income tax. My books were subject to numbers 4 and 6. That is, 10% for sales tax, and 7.5% for income tax. The base was my books' CIF value minus $50, or $274.37.
OK, I paid a lot for the books. But I am fine: the people in the Post Office and in the Customs&Excise Office were very nice and helpful. They showed me all the regulations related to my questions. And I understand. If it's transparrent and lawful, I pay. No harm done.
(SBY, I vote and I pay tax. Watch your back!)