Extremely useful information - unfortunately I just assumed this didn't apply to me because I am in the UK and not the EU. Another mistake, though given it's not huge amounts of money I will chalk it up to experience.
Hopefully someone else will benefit from this helpful advice.
https://aws.amazon.com/blogs/aws/free-data-transfer-out-to-i...
But. Don't leave it until the last minute to talk to them about this. They don't make it easy, and require some warning (think months, IIRC)