From "Russell Coker" <russell@coker.com.au>
http://aws.amazon.com/ec2/#pricing
A "small" EC2 instance costs 6 cents per hour or $43.80 per average month. Plus costs for bandwidth and storage. A "micro" instance costs 2 cents per hour or $14.60 per average month. .. EC2 is really good for dynamically scalable systems and for situations where you need bulk computing off-peak (as demonstrated in a LUV talk some time ago). It's not particularly good for running a single server.
As said, it is an announcement server which is "fed" by us maybe once a month. The idea was to let it run only when needed. I wasn't aware of SMTP traffic restrictions. I actually looked out for it but could not find it mentioned anywhere. Besides, for me it was a trial to figure out how to deal with Amazon EC2. Well, actually, fears confirmed: you never know exactly what you get, you cannot rely on it and you don't get what you want;-) Thanks for the other ideas as Linode or Hetzner. I have a think about it. Regards Peter