Showing Robot is a premium add-on for your Showing Suite account. It is not free.
However, as an individual listing agent, you get 5 free listings to utilize the Showing Robot service. Think of this as a "trial" of the Showing Robot system, or a "test drive". You can see how you like the service, and if you want to extend usage to all of your listings, you can enable it beyond those 5 listings at a consistent and low rate.
The rate for each listing enabled with Showing Robot is $5 per listing/month.