# gem install aws-sdk

require 'aws'


PRICE_PER_GB_MONTH = 0.11

ACCESS_KEY = '...'
SECRET_KEY = '...'
ENDPOINT = 'eu-west-1.ec2.amazonaws.com'

ec2 = AWS::EC2.new(:access_key_id => ACCESS_KEY, :secret_access_key => SECRET_KEY, :ec2_endpoint => ENDPOINT)

cost_per_month = AWS.memoize do
  ec2.volumes.reduce(0) { |sum, volume| sum + volume.size } * PRICE_PER_GB_MONTH
end

puts sprintf('$%.2f/month', cost_per_month)