Most of the parts I purchase from the US I ask to have sent using a USPS flat rate box, Small about $14 for up to about 1kg, Med around $45 for up to 10kg. If the seller wont then I look elsewhere, if it's a hard to find bit and I have to pay unreasonable postage I make sure I check the amount they have actually paid to send it, if they have ripped me off I contact the seller saying, I see you have found a better price on postage and ask for a refund to my paypal account before I leave "feedback". This advice was given to me a while back by a mate and I have found that most will give a refund rather than recieve bad feedback. Works for me.