I have trouble understanding arrays and enums. When and how?

Hello everyone!

I am writing the code of a market system, where you buy and sell and manage prices. My problem is as the title says; I think its time to use arrays or enums. Well the actual problem is that i do not know when or how to use them. Here for example look at a piece of my code:

     float foodBuyPrice;
     float woodBuyPrice;
     float planksBuyPrice;
     float stoneBuyPrice;
     float ironBuyPrice;
     float nailsBuyPrice;
     float clayBuyPrice;
     float bricksBuyPrice;
 
     float foodSellPrice;
     float woodSellPrice;
     float planksSellPrice;
     float stoneSellPrice;
     float ironSellPrice;
     float nailsSellPrice;
     float claySellPrice;
     float bricksSellPrice;
 
     Text foodBuyText;
     Text woodBuyText;
     Text planksBuyText;
     Text stoneBuyText;
     Text ironBuyText;
     Text nailsBuyText;
     Text clayBuyText;
     Text bricksBuyText;
 
     Text foodSellText;
     Text woodSellText;
     Text planksSellText;
     Text stoneSellText;
     Text ironSellText;
     Text nailsSellText;
     Text claySellText;
     Text bricksSellText;
 
     Text foodAmountText;
     Text woodAmountText;
     Text planksAmountText;
     Text stoneAmountText;
     Text ironAmountText;
     Text nailsAmountText;
     Text clayAmountText;
     Text bricksAmountText;
 
     Script_Economy economyScript;
     Script_Stock stockScript;
 
     void Awake () {
         economyScript = GetComponent<Script_Economy> ();
         stockScript = GetComponent<Script_Stock> ();
     }
     
     void Update () {
         foodBuyText.text = foodBuyPrice.ToString ();
         woodBuyText.text = woodBuyPrice.ToString ();
         planksBuyText.text = planksBuyPrice.ToString ();
         stoneBuyText.text = stoneBuyPrice.ToString ();
         ironBuyText.text = ironBuyPrice.ToString ();
         nailsBuyText.text = nailsBuyPrice.ToString ();
         clayBuyText.text = clayBuyPrice.ToString ();
         bricksBuyText.text = bricksBuyPrice.ToString ();
 
         foodSellText.text = foodSellPrice.ToString ();
         woodSellText.text = woodSellPrice.ToString ();
         planksSellText.text = planksSellPrice.ToString ();
         stoneSellText.text = stoneSellPrice.ToString ();
         ironSellText.text = ironSellPrice.ToString ();
         nailsSellText.text = nailsSellPrice.ToString ();
         claySellText.text = claySellPrice.ToString ();
         bricksSellText.text = bricksSellPrice.ToString ();
     }
 
     public void PurchaseFood () {
         if (economyScript.wealth > foodBuyPrice) {
             economyScript.wealth = economyScript.wealth - foodBuyPrice;
             stockScript.foodAmount++;
         }
     }

It's so long! So messy! What would be a good way of handling this?

I do not care for having a code wrote for me; I merely want to learn how and when to use arrays and enums so that, in the future, I may not find myself with problems like this again. Thanks a lot in advance!