I just found this: http://www.usps.com/prices/priority-mail-international-prices.htm To be honest, this could very well bury the postal service in labor and fuel costs, BUT it's a great deal for people that can use it well More on boardgamegeek.com

What is the price of shipping without using a flat rate? More on reddit.com

EMS is Global Express Guaranteed. There are no flat rate options for GXG. Priority Mail Express International only has one option for flat rate, that being envelopes. Priority Mail International can use the specified boxes on this page: https://pe.usps.com/text/dmm300/notice123.htm#_c313 - You can have the boxes mailed to you for free by going here: https://store.usps.com/store/shipping-supplies/international/_/N-6vj2li - it also has the international flat rate express envelopes. The easiest way to do the customs forms and purchase discounted labels would be to use https://www.pirateship.com/ - there's no membership fee to use that service, just gotta register an account and purchase the labels with a US credit card. If the purchaser is in Europe, Middle East or SE Asia, every item within the package has to also have a HS harmonized tariff code as well as country of origin. Make sure you read the country's conditions of mailing - many countries ban a variety of items, often international buyers will try to buy things which their country bans, you're responsible for what you mail. You can find the listings for each country (including group codes for the notice 123 price list) here: https://pe.usps.com/text/Imm/immctry.htm More on reddit.com

Depends on the box / envelope. Some of the flat rate boxes are just domestic, and some will be domestic and international. It will say it clearly on the box. If it says "domestic and international", then there will be two rates. More on reddit.com