Add Item to inventory - Shop UI intro and setup

Hi there,

as mentioned in the question, I did the Shop UI live training and added a player inventory and a vendor inventory to my game. Now I messing around picking up an item and put it in the players inventory. Probably this question had been asked but I can't find it. Sorry for that. Hope this is the right place to ask beginner questions.

the ShopScrollList (from tutorial link text) script populates the players inventory and sends items to the vendors shop. This works.

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 using System.Collections.Generic;
 
 [System.Serializable]
 public class Item
 {
     public string itemName;
     public Sprite icon;
     public float price = 1;
 }
 
 public class ShopScrollList : MonoBehaviour {
     
     public List<Item> itemList;
     public Transform contentPanel;
     public ShopScrollList otherShop;
     public Text myGoldDisplay;
     public SimpleObjectPool buttonObjectPool;
 
     public float gold = 20f;
 
 
     // Use this for initialization
     void Start () 
     {
         RefreshDisplay ();
     }
 
     public void RefreshDisplay()
     {
         myGoldDisplay.text = "Gold: " + gold.ToString ();
         RemoveButtons ();
         AddButtons ();
     }
 
     private void RemoveButtons()
     {
         while (contentPanel.childCount > 0) 
         {
             GameObject toRemove = transform.GetChild(0).gameObject;
             buttonObjectPool.ReturnObject(toRemove);
         }
     }
 
     private void AddButtons()
     {
         for (int i = 0; i < itemList.Count; i++) 
         {
             Item item = itemList[i];
             GameObject newButton = buttonObjectPool.GetObject();
             //newButton.transform.SetParent(contentPanel,false);
             newButton.transform.SetParent(contentPanel,false);
             newButton.transform.localScale = new Vector3 (1.0f, 1.0f, 1.0f);
 
             SampleButton sampleButton = newButton.GetComponent<SampleButton>();
             sampleButton.Setup(item, this);
         }
     }
 
     public void TryTransferItemToOtherShop(Item item)
     {
         if (otherShop.gold >= item.price && otherShop.isActiveAndEnabled) 
         {
             gold += item.price;
             otherShop.gold -= item.price;
 
             AddItem(item, otherShop);
             RemoveItem(item, this);
 
             RefreshDisplay();
             otherShop.RefreshDisplay();
             Debug.Log ("enough gold");
 
         }
         Debug.Log ("attempted");
     }
 
     void AddItem(Item itemToAdd, ShopScrollList shopList)
     {
         shopList.itemList.Add (itemToAdd);
     }
 
     private void RemoveItem(Item itemToRemove, ShopScrollList shopList)
     {
         for (int i = shopList.itemList.Count - 1; i >= 0; i--) 
         {
             if (shopList.itemList[i] == itemToRemove)
             {
                 shopList.itemList.RemoveAt(i);
             }
         }
     }
 }

My attempt: My script attached to a GameObject should get an item to the inventory. Therefore I create a new Item class where I choose 1 or more objects and want to call the AddItem function from the code above to do so:

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 [System.Serializable]
 public class pickupitem
 {
     public string itemName;
     public Sprite icon;
     public float price = 1;
 }
 
 public class AddItem : MonoBehaviour {
     public ShopScrollList playerpocket;
     public List<pickupitem> itemListforpickup;
     //public GameObject playerpocket;
     public ShopScrollList shopscrolllist;
 
 
     void OnMouseUp()
     {
         shopscrolllist.AddItem (pickupitem, playerpocket);
     }
 }

Is this a way to approach or is it totally ineffective? Is there a better way? What is wrong with the code? Is there a tutorial that comes after the above mentioned that handles such things?

Thank you guys