USPS first class is the best. If you have an idea of how much your items weigh (for me things are pretty much 4oz, 8oz, or 16oz) you can go to the USPS site and see how much it would be to ship this weight to certain countries that buy a lot on etsy. (for me its: Australia, Canada, UK, certain places in Asia etc). I have a round about figure, pay the difference when I get an order (if need be) and change my prices to the exact cost once I've shipped to internationally. Yes, I've lost a few dollars doing this but I have benefited from a lot of international business. Good Luck!