Why does the money counter resets when I pull different objects trough the trigger?

I need help! I'm making a game where you earn money if you pull an object (with the tag "Valuable") trough a trigger. The problem is that it starts counting from 0 every time the trigger is triggered by a different object. If you pull the same object trough the trigger several times, the counting works, but I want it to destroy the object so you can't pull it trough the trigger several times.

Here is the code which is assigned to the object I want to sell:

 using UnityEngine;
 using TMPro;
 
 public class Valuable : MonoBehaviour
 
 {
     public TextMeshProUGUI countText;
     private int count;
 
     // Count = Money
     void Start()
     {
         count = 0;
     }
 
     void SetCountText()
     {
         countText.text = "Money: $" + count.ToString();
     }
 
 
 // When something goes trough the trigger, it will add money and destroy the object
 private void OnTriggerEnter(Collider other)
     {
         if(other.gameObject.CompareTag("SellObject"))
         {
             other.gameObject.SetActive(true);
             count = count + 500;
 
             SetCountText();
             Destroy(gameObject);
         }
     }
 }