You can check how much money (dappers) your character possesses in the money section (money) at the bottom of your inventory.

Upon arriving in Atys, your character is totally penniless. What's more, without money, you would find it impossible to progress. You would not be able to buy the best items for example.
There are several ways to earn a living on Atys:

Missions:

When you complete missions successfully, the NPC who sent you on the mission will often pay you using money.

Loot:

If you manage to hunt down a creature, it is possible to retrieve raw materials from it. You can then sell these to NPC traders or to crafter players.

Once the creature has died, double-click on its remains to open window where you can view the raw materials. You can choose to take certain items by clicking on the icons or take everything by clicking on the "take all" button (take all).

If you manage to defeat an NPC enemy, you can also plunder its remains. Follow the same procedure as with a creature. You may also find money or objects that can be sold.

Note: that you can only recover raw materials or other items from enemies that you or your group have killed.

Raw materials from the ground:

The activities of prospecting and extraction allow you to recover raw materials that you can then sell.