message: add in link to polly pricing
diff: @@ -9,6 +9,7 @@ Some Useful References:
  | Author | Link |
  | ------------- | ------------- |
  | Amazon Polly | [Amazon Polly Site](https://aws.amazon.com/polly/) |
  +| Pricing | [Polly Pricing](https://aws.amazon.com/polly/pricing/) |
  | AWS Blogs | [Giving your content a voice with the Newscaster speaking style from Amazon Polly](https://aws.amazon.com/blogs/machine-learning/giving-your-content-a-voice-with-the-newscaster-speaking-style-from-amazon-polly/)
  