Pricing is calculated based on the number of mailbox calendars you want to publish. The minimum number of licenses is 10, and you can get any number of licenses from there. You can select the calendars you wish to read / publish; you don’t need to license the whole global address list. In AgendaX you create groups (e.g. Sales, Marketing, etc. or Location 1, Location 2, etc.) and for each group you select members from the GAL (distribution lists or individual mailboxes). A mailbox can be part of multiple groups and is only calculated as one license. The total number of all members of these groups determines the number of licenses you need.
The number of AgendaX web application users is irrelevant. Only the total number of published mailbox calendars determines the licenses needed.