Everything here is my opinion. I do not speak for your employer.
May 2013 →
1 Gbps, fully saturated, is 324,000 Gbytes per month.
According to the Amazon EC2 calculator, that would cost your EC2 instance $22,373.57. (Also they'll throw in a virtual computer worth $14.64/month :))
Conclusion: $70/month is a pretty good deal.