How to Create Your List for Free
Create and publish a 'Thank You' page
Create a new page to thank your readers for subscribing. Don’t use “thank-you” in the permalink as people may guess that and bypass the signup process. Make sure that your thank you page does not appear in any menu. You want only your subscribers to see this.
This should not be SEO friendly because you don't want the search engines to find it. So don’t add tags and use your SEO plugin to make the page “noindex” and “nofollow”.