ECONOMY:
1. You earn money by killing other people. Each kill earns you some money.

2. Besides getting money from kills, there's another thing that can make you a fortune - Emeralds
Those are obtainable in 2 ways:
2.1 from vote parties which happen once the goal for voting is reached (you can use /vp command to see the current count, or just look at the sidebar where it says Vote Party)
2.2 from Emerald generators which you can find around the map
Emeralds can be sold in multiple places such as shop, signs, signs in donatorsrooms (Thing for ranked people to sell those a bit faster - /ewarp DonatorsRooms), prestiges (higher the prestige, higher the price for selling).

3. Every hour there is an envoy event which gives a variety of rewards (money, emeralds, ender pearls, enchanted apples or a special tier based weapon). There are 3 Tiers of Envoy chests, good luck finding them! :D