Hello,
we have mentioned several times that service is premium and an account has free trial. Please look in plugin short description, main description, FAQ and plugin settings (license agreement URL).
CleanTalk is premium anti-spam service for WordPress, please look at the pricing. The plugin works with cloud anti spam service CleanTalk. CleanTalk has free trial.
And this,
Is it free or paid?
The plugin is free. But the plugin uses CleanTalk cloud service to filter spam bots. You have to register an account and you have free trial to test anti-spam for comments, registrations, bookings, contacts or orders. When the trial (on CleanTalk account) is finished, you can renew the subscription for 1 year or deactivate anti-spam plugin.
Could you please change your reivew?