The main currency in Prodigy are Gold Coins. It can be used to purchase any type of item or pets and can be obtained from battles or quests. Defeating monsters will usually result in 100 Gold Coins, increasing by 100 for every other monster if there are more than one.
Trade in this currency by speaking to Merchants to obtain Boots, Buddies, Hats, Outfits, Pets, Rings, and Wands. You can also use it in your house to purchase different variants of houses and Dorm items.
There are other types of currency than just Gold Coins which are Candy Corn, Relic Coin, Star Shards, Magic Snowflakes, Dragon Flies and Wood.
Candy Corns are the primary currency for the Pumpkinfest which occurs yearly for the month of October, and can only be used during this event. They can only be gotten during this event by battles and rescuing pumpkins by relighting them or defeating the monster that has taken over it. It's known use is only for trading them to Julia Ghoulia for Dorm items, Hats, Outfits, and Wands.
Magic Snowflakes are the primary currency for the Winterfest which occurs yearly, and can only be used during this event. They can only be gotten during this event by finding Snowmans in Lamplight Town and defeating the monster inside.
Relic Coins (used and known as copper coins) are common in Dyno Dig sites, post-battle reward chests, and more. It's known use is only for trading them to the Toy Merchant (known as Wandering Wares) for epics gear.
Star Shards are the primary currency for the Starlight Festival which is held in November, and can only be used during this event. They can only be gotten by going through Wizard battles or clicking on a fallen star in Lamplight Town or defeating a monster trying to capture it. It's known use is only for trading them to Mama Star for Starlight Festival items.
Dragon Flies are the currency for 2017's Starlight Festival, and can be gotten with the same method as Star Shards.
Wood is a type of currency found only in The Lost Island. The only way to get Wood is by completing the daily quests given by Swoopy. It is presumed to be used as a currency in the future, but is currently just an item.