I buy items from Japanese sellers on eBay frequently. I'm in the US, and I have never owed customs on items shipped EMS, delivered through the US Postal service. I did buy a watch, though, from eLady that was shipped by FedEx and I owed $125 in customs on it. It depends on the shipping service.
Same experiences. Though it has been some years now, when I bought from Japan delivered EMS I paid no customs.
But, when I ordered from (UAE? Dubai?) it was delivered Fedex and I later got a bill from Customs.