To subscribe to a streamer, navigate to his or her profile, and then click “Subscribe” at the top of the page. If this is the first time you've subscribed to a streamer from your Twitch Prime account, you'll be asked if you want to use your monthly free subscription for this streamer.

How do I subscribe to Amazon Prime?

To subscribe to a streamer, navigate to their profile and click “subscribe” at the top of their page. If it is the first time you've subscribed to a streamer using your Twitch Prime account, Twitch will prompt you to ask if you want to use your monthly free subscription for this streamer.

Why can I not subscribe with Twitch Prime?

Make sure that you are not using a trial of Amazon Prime of any type. Also make sure on your subscriptions page that there is not an active sub there.