If approved you can, as mentioned, charge people to access your server, charge for in-game advertising, and theoretically charge for cosmetic items - the stipulation being that sold items must not affect gameplay. In order to be able to monetise your server it must be approved by Bohemia, and those that are will be added to a publicly available list.

Private DayZ servers can now be monetised, which means you can - among other things - limit access to people who pay.