Thank you for your interest in our project and for your pledge!
I know it seems like a lot for postage but we have tried to keep it as low as possible and are not even covering our full costs. If we receive a high volume of pledges from the USA we may be able to do something to bring that cost down. We'll be keeping all our backers updated! I hope that helps.
Don't see the answer to your question? Ask the project creator directly.