Most CTAs scroll off the screen and out of mind. Floating CTA pins a small product bar to the bottom of your post and keeps it there while people read: name, star rating, price, and a buy button that's always one tap away. It's free, about 3KB, no jQuery, no account, and you set it per post so the bar matches the page. Built for review and affiliate content, but it works anywhere you want one clear action to follow the reader down the page. Free on WordPress.org.