writeItemValue
Writes the value into the persistent data container. This is used to only ever calculate item worth once. The weakness with this system is that if admins change the price scaling, the changes will not affect older items. This is still worth it to only ever calculate the price of items once, as mass calculating item prices can be costly. Also, item values will be updated with each lore refresh. NOTE: This is the item value, not the resale value. These are two very different values!
Parameters
itemStack
ItemStack to register the value onto.
player
Player associated to the ItemStack. This is necessary because different prestige tiers will result in different prices.