There are 3 types of currency in Warface: Game Money, Credits and Crowns.
Game Money 
This is the earned in-game currency that is earned by playing matches. Almost all items can be bought with this currency. This currency is used to purchase Shop items.
Credits 
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This is the bought in-game currency that is earned by purchasing it with real money. This currency is mainly used to purchase resurrection coins (to respawn in PvE missions) and Boosters to boost EXP, $, and VP.
Crowns
A small portion of the weapons, outfits, etc. can be bought with this type of currency. It is earned by completing PvE missions in a timely fashion and with a high score. These can also be earned by completing the contracts. Items bought with crowns provide greater stats.