7 easy tips to reduce your Amazon ec2 cloud costs

Use cnames instead of A records
do not map your domain name to an elastic ip. Map it to the public domain name of the instance. Let’s say you have a machine with name splunk.gumgum.com. All the web servers (within the same availability zone) send considerable data to this machine. If you setup splunk.gumgum.com as an A record, your data will go out and come back in. But if you map it as cname, your data will always remain within the ec2 cluster. To read more about this visit Eric Hammond’s Using Elastic IP to Identify Internal Instances on Amazon EC2 post.

Use spot instances
Use spot instances whenever possible. Spot instances cost less than on demand instances. You can read more about sport instances on Amazon’s web page. There is a website that shows spot history price graphs. It will tell you an average price of various types of instances. The average price of a m1.small sport instance is 3 cents an hour. You pay 8.5 cents an hour for the same type of on demand instance.
(Link: 7 easy tips to reduce your Amazon ec2 cloud costs)