If you actually USE 10gpbs your data transfer bill is going to be around $167k per month (That's for transferring 3.34PB).
Actually, a bit higher than that since I calculated all based on the cheapest tier EC2 will quote on the web, 5 cents per gigabyte.
For a one time 3TB download to an EC2 instance, priced at the first pricing tier of $0.12/gigabyte, that transfer will cost $360, and take around 40 minutes.