Keeping EC2 Free Instances Free

Question

I signed up for Amazon AWS's Free Tier instance. Everything works fine so far, but I'm a bit confused about how to make sure I won't have to pay for it.

Specifically, I've been billed a bit for "Elastic IP address not attached to a running instance per hour on a pro rata basis".

In the Management Console > Elastic IPs section, I have allocated a new Elastic IP and attached it to my instance. It seems that I can allocate 4 more addresses, but not attach them, this is only possible for one instance. How do I avoid being billed for unattached Elastic IPs? Is there even a way, if I have 5 Elastic IPs assigned to my account, but only have one instance?

I'm also not sure how the traffic usage reports work - I think I'm allowed "*15 GB of bandwidth out aggregated across all AWS services", but only if I use the Public DNS and not the Elastic IP. Is this correct?

Answer 1

Amazon has only a limited number of Elastic IP addresses. So, if you reserve an Elastic IP and then don't use it, they will charge you. Always attach your Elastic IP's to running instances and release them when you do not need them anymore.