Steve is right. Generally, there are no customs barriers at all coming into the States. Local taxes imposed by the different states might intervene in rare cases, but as a rule it all goes through untariffed.
Europe is another matter, where Customs tariffs are the norm, particularly in Scandinavia. Holland is pretty good, but Norway, Denmark and Sweden in that order are terrible to high, with 25% of declared value being typical. I've even had Customs officials go to the website and figure tarriffs on the basis of the posted price, NOT the declared value, which is not a game I like to play at all. Central and Eastern Europe are appalling, with up to 80% of declared value common, and some Asian countries are high (and unpredictable!).
OTOH, I have had people send me their AKSAs for repair and had the damaged goods up for Australian Customs and lengthy retrieval! In Australia they will want 10% of declared value plus an admin fee of just under $50 , but the real problem is retrieval. If you do it yourself to save money, it takes about four hours and involves driving about 50 kms. The documentation is arcane and complex, and the Customs people don't really want to help you as they want it all done through forwarding agents, who charge typically $100. So if you send me an AKSA for repair, say so, don't put a value on it of more than a couple hundred dollars!!
Cheers,
Hugh