New equipment is automatically equipped upon purchase, revealing the next upgrade in the item store. Every successive upgrade will cost more than the one that was just bought. You can equip previously purchased equipment through the equipment tab in your Inventory.
Health potions are single-use only and do not appear in your inventory; these items take immediate effect upon purchase.
Once you have reached level 10 and selected your class, class-specific equipment will become available in the item store. Additionally, special class-specific equipment is made available for a limited time during Grand Galas.
If you have died or used an Orb of Rebirth, the equipment you have lost will appear in the Item Store to allow you to repurchase it, even if it is limited edition equipment that is not normally available. However to repurchase lost class-specific equipment, you must first change to the correct class.