How to get various items in the game:

Giggitywatts:  You can recycle un-used cards and you can also get this item from rewards / quests.

What you can do with them:  Used to upgrade cards

Coins:  Coins can be earned in the arena and from events.  Animation Throwdown seems to have endless events so it’s always a good place to get coins.

What you can do with them:  Used to buy extra cards, upgrade cards and start a guild.

Gems: You can buy gems for real money and I have received some as rewards from various quests.

What you can do with them:  Used in the shop, buy cards, speed up research, refill energy…pretty much anywhere to encourage you to buy more with real money.

Wonder Wharf Coins: You earn these in challenge battles.

What you can do with them:  Used to purchase items in the Challenge shop.

Hero Tokens:  You can randomly earn hero tokens in area battles.

What you can do with them:  Used to upgrade / level up your hero.

Gold Turds: You can earn these as rewards or in the adventure section.

What you can do with them:  Used to open various things in the store.

Stones:  There are various types of stones and you can mostly earn them through special events.

What you can do with them:   Merging a lot of them together (of the same type) will give you special cards.