…to get rid of the ‘nags’ and ‘ads’ on the right side of the Yoast SEO Settings Page, you can buy Yoast or look in this directory: YourWebSitesRootDirectory/wp-content/plugins/wordpress-seo-premium/admin/views
look for this file: sidebar.php and delete all the contents of the file and save the empty file.
No more ads, no more nags.
I tested it and did not lose any functionality. I also looked at the code and every function referred to the yoa.st web site, so there really isn’t any functionality in the PHP code other than to nag and present ads.