Added in pricing description. (home-assistant#2033)

Carlo Costanzo · fabaff · commit 583c7c1483b7 · 2017-02-14T10:14:08.000+01:00
Links to pricing.
diff --git a/source/_components/tts.amazon_polly.markdown b/source/_components/tts.amazon_polly.markdown
@@ -13,6 +13,7 @@ ha_release: 0.37
 ---
 
 The `amazon_polly` text-to-speech platform that works with [Amazon Polly](https://aws.amazon.com/polly/) to create the spoken output.
+Polly is a paid service via Amazon Web Services.  There is a [free tier](https://aws.amazon.com/polly/pricing/) for the first 12 months and then a charge per million characters afterwards.
 
 To enable text-to-speech with Amazon Polly, add the following lines to your `configuration.yaml`:
 
