Your pricing plan depends on the number of products which the application is applied to. We adjust your plan every 30 days according to the number of products in subscription rules you had in this period for the last 30 days.
For example, you have 15 products in rules on the first day of the 30-day period. You will pay $19,95 after 30 days even if you don't have any products in rules on the last day of the 30-day period.