As you progress through the stages you will eventually reach the point where you will be able to upgrade the prince's abilities and weapons. These upgrades are available at the in-game store and require you to spend the coins you earned through battle. You can buy revival potions to revive near to where you died, elixirs to increase your maximum health, health potions that give you a pick-me-up whenever you may need it, and swords and combo upgrades to give you an edge in combat. There is aways the option if you do not have enough coins of opening your wallet and buying them using real money.