The users are counted by the distinct individuals requesting pages with Acobot installed in a calendar month, regardless of how often they visit. When the quota is exceeded, Acobot hides with no impact on your website.
There is no limitation to the volume of interaction, sales leads or conversions for each paid plan. When picking a plan, you pick the one matching your website traffic.
Free registration. Free setup. No credit card required. Unlimited usage. You even don't need to install it for evaluating your chatbot.