I'm wondering how much more expensive it would be to access my EC2 instance from a different country than if I just waited until I was back at home. I could wait, but it might be good to see the international rates for use.
I'm sending it http requests within an iOS app to query my database. My app does also have GPS data, so I guess I'm thinking getting a completely different location into the database would help with test cases.
If you are always accessing your app from the Internet, then there will be no change in the access charges.
The cost for Data Transfer is charged if traffic goes out to the Internet. it doesn't matter where on the Internet.
One exception to this is if you are using Amazon CloudFront, which is a global caching service and charges different rates depending upon from where traffic is served.