To use ElastiCache, you need an AWS account. If you don't already have one, you'll be prompted to create one when you sign up. You're not charged for any AWS services that you sign up for unless you use them.
To sign up for ElastiCache
Open http://aws.amazon.com/, and then click Sign Up.
Follow the on-screen instructions.
Part of the sign-up procedure involves receiving a phone call and entering a PIN using the phone keypad.