One price per active person, per month. Unlimited questions, unlimited sources on paid plans. A person who does not ask anything in a month is not billed for it.
Only people who asked at least one question in the month are billed. Most companies pay for 60 to 80% of their seats.
Start with TeamSomeone who asked at least one question in the calendar month, in the app or through a developer URL. Members who did not ask are not billed that month.