If you've tried and have decided that it's not for you, you can cancel your Prime membership.
And, if you subscribe via your Twitch Prime membership, you can do so without spending a dime! For instance, you can unsubscribe using the Google Play Website, or Twitch Mobile app, or Google Play Subscription center.
You will have to relink your accounts to redeem the offers.
With original content being the key to making it on Twitch, viewers are keen to support up-and-coming streamers that they so dearly love.