Yes. If you already have Oura Ring your first 3 months of Clue Plus are on us.
You can subscribe to Clue Plus via https://helloclue.com/voucher. Just create a Clue account, and then enter your unique Clue Plus code which was sent to you via email from Oura. You can then download Clue from your app store, sign in to your account, and start using Clue Plus.
Once your 3 free months are up you can continue using the Oura integration by subscribing to Clue Plus by following these steps.