One problem I've had lately is when vendors mark a lower than actual price on the package. It seems that customs has the right, if they disagree with what's written on the shipping label, to just guess what they think it should be worth instead. I've ordered something for 65US, had it marked as a 20US value by the shipper, and charged gst and duty fees for a package worth $165 Canadian dollars!!!! That one really infuriated me, but the problem is if you want your package, you're stuck paying out the ass for it.