The Arcstone Pack is an Item Pack for Creativerse purchasable in the ingame Store for Coins that can be bought with real money via Steam Wallet. Coin Packs can also be purchased via Store, to be found in the "Coins" TAB.
The price of the Item Pack can differ depending on sales times, and the price of Coins can be very different depending on the country you live in.
This item kit contains:
20 Arcstones.
Arcstones can otherwise be obtained from common blue Keepas, Silver Keepas or Golden Keepas either by killing them or by taming them, feeding them and then harvesting from them. The rare Silver Keepas and Golden Keepas will provide you with much more Arcstones when you kill then than when you make them your Pets.
After your purchase of the Arcstone Pack you will find an icon symbolizing this item pack in your inventory/bag that you can "claim" once on one specific game-world of your choice.
When claiming Item Packs, you will then find the purchased items in your inventory or in any free quickslot. Often these items will be packed in a storage container that looks like a staple of crates and only takes up 1 slot of your inventory or quickbar. You can place this storage container into the game-world and access it like any other storage object by right-click or typing "f" (as the default key) while looking at it.
The price is for one item pack only, so you cannot claim the same pack a second time, neither on the same game-world nor on another.