NedFox is completely right.
From February 1st 2015, anyone is allowed to monetize their Arma 3 server as long as they're registered, approved and listed on https://www.bistudio.com/monetization/approved:
Monetization happens when players, unlike with donations, receive some kind of reward or perk for their money. This requires our approval. Some examples of allowed rewards are perks which do not affect gameplay, e.g. custom textures, skins, forum badges, reserved slots, product placement, in-game advertising and sponsorship. You can also sell in-game items which do not affect gameplay in any way (e.g. special hats, designed shirts with logos, etc.) – generally everything cosmetic is allowed.
On the other hand, perks and rewards such as providing in-game money, weapons, ammo, vehicles, discounts, vehicle spawns, housing and any other gameplay affecting features are not allowed and will not be approved.