It's also true that the base USPS postal rate for First Class mail to international locations (includes tracking but does not guarantee tracking information at the destination country and does not offer insurance), is actually pretty expensive. Typically around $15 to most destinations for a base price for a package of any weight, and scales up quickly around half a pound - if you go with priority which is faster, gives you point to point tracking, and is insured to $200, it starts at $32 or so. Recently I've got some much better rates shipping small items internationally and paying for postage with paypal (still USPS), but it does not factor into ebay's shipping calculator, and if you purchase the postage through ebay instead (or at a retail location), it may actually be the calculator's price.
While some countries offer reasonable small parcel postage to international destinations, the US hasn't really been one for a while, though perhaps the rates you're seeing are still higher.