Variable should have a value but if i start the game, the value resets to 0

The error may be simple, but I'm bad at coding. I'm making an upgrade system for my game. The problem is, that the cost of the upgrade is set in the code to 400 but if i start the game, it changes to zero. How do I fix the cost? Btw sorry for the long code

 //upgrade count text
 public Text HealthUpgradeText;
 public Text DamageUpgradeText;
 public Text CritChanceUpgradeText;
 public Text CritMultiplierUpgradeText;
 
 //Cost text
 public Text HealthUpgradeCostText;
 public Text DamageUpgradeCostText;
 public Text CritChanceUpgradeCostText;
 public Text CritMultiplierUpgradeCostText;
 

 //How much
 private float HealthUpgradeValue = 5f;
 private float DamageUpgradeValue = 1f;
 private float CritChanceUpgradeValue = 0.5f;
 private float CritMultiplierUpgradeValue = 1f;
 
 
 //How much upgraded
 private int HealthUpgradeCount;
 private int DamageUpgradeCount;
 private int CritChanceUpgradeCount;
 private int CritMultiplierUpgradeCount;
 
 //Maximal Upgrades
 private const int HealthUpgradeMax = 100;
 private const int DamageUpgradeMax = 100;
 private const int CritChanceUpgradeMax = 50;
 private const int CritMultiplierUpgradeMax = 100;
 
 //How much which upgrade cost
 private float HealthUpgradeCost = 300f;
 private float DamageUpgradeCost = 300f;
 private float CritChanceUpgradeCost = 300f;
 private float CritMultiplierUpgradeCost = 300f;

 private void Awake()
 {
     //Playerstats
     _playerStats = FindObjectOfType<PlayerStats>().GetComponent<PlayerStats>();
     AllMoneyText1 = FindObjectOfType<AllMoneyText1>().GetComponent<AllMoneyText1>();
     
     //Load the upgrade count
     HealthUpgradeCount = PlayerPrefs.GetInt("HealthUpgradeCount", 0);
     DamageUpgradeCount = PlayerPrefs.GetInt("DamageUpgradeCount", 0);
     CritChanceUpgradeCount = PlayerPrefs.GetInt("CritChanceUpgradeCount", 0);
     CritMultiplierUpgradeCount = PlayerPrefs.GetInt("CritMultiplierUpgradeCount", 0);
     
     //Load costs
     HealthUpgradeCost = PlayerPrefs.GetFloat("HealthUpgradeCost", 300f);
     DamageUpgradeCost = PlayerPrefs.GetFloat("DamageUpgradeCost", 300f);
     CritChanceUpgradeCost = PlayerPrefs.GetFloat("CritChanceUpgradeCost", 300f);
     CritMultiplierUpgradeCost = PlayerPrefs.GetFloat("CritMultiplierUpgradeCost", 300f);
     
     //Load the Texts
     HealthUpgradeText.text = HealthUpgradeCount + "/" + HealthUpgradeMax;
     HealthUpgradeCostText.text = HealthUpgradeCost + "$";
     DamageUpgradeText.text = DamageUpgradeCount + "/" + DamageUpgradeMax;
     DamageUpgradeCostText.text = DamageUpgradeCost + "$";
     CritChanceUpgradeText.text = CritChanceUpgradeCount + "/" + CritChanceUpgradeMax;
     CritChanceUpgradeCostText.text = CritChanceUpgradeCost + "$";
     CritMultiplierUpgradeText.text = CritMultiplierUpgradeCount + "/" + CritMultiplierUpgradeMax;
     CritMultiplierUpgradeCostText.text = CritMultiplierUpgradeCost + "$";
 }

 private void Update()
 {
     
 }

 public void UpgradeHealth()
 {
     //Get the saved values
     HealthUpgradeCount = PlayerPrefs.GetInt("HealthUpgradeCount");
     HealthUpgradeCost = PlayerPrefs.GetFloat("HealthUpgradeCost");
     //Check if money too low or max upgrade count reached
     if (_playerStats.AllMoney < HealthUpgradeCost || HealthUpgradeMax <= HealthUpgradeCount)
         return;
     //Increase stats
     _playerStats.playerHp += HealthUpgradeValue;
     _playerStats.MaxPlayerHp += HealthUpgradeValue;
     //Subtract money
     _playerStats.AllMoney -= HealthUpgradeCost;
     //Increase cost and count
     HealthUpgradeCost += 50;
     HealthUpgradeCount++;
     
     Debug.Log(HealthUpgradeCost);
     //Change text
     AllMoneyText1.moneyText.text = _playerStats.AllMoney + "$";
     HealthUpgradeText.text = HealthUpgradeCount + "/" + HealthUpgradeMax;
     HealthUpgradeCostText.text = HealthUpgradeCost + "$";
     //Save new values
     PlayerPrefs.SetFloat("HealthUpgradeCost", HealthUpgradeCost);
     PlayerPrefs.SetInt("HealthUpgradeCount", HealthUpgradeCount);
     PlayerPrefs.SetFloat("AllMoney", _playerStats.AllMoney);
 }
 public void UpgradeDamage()
 {
     //Get the saved values
     DamageUpgradeCount = PlayerPrefs.GetInt("DamageUpgradeCount");
     DamageUpgradeCost = PlayerPrefs.GetFloat("DamageUpgradeCost");
     //Check if money too low or max upgrade count reached
     if (_playerStats.AllMoney < DamageUpgradeCost || DamageUpgradeMax <= DamageUpgradeCount)
         return;
     //Increase stats
     _playerStats.playerDmg += DamageUpgradeValue;
     //Subtract money
     _playerStats.AllMoney -= DamageUpgradeCost;
     //Increase cost and count
     DamageUpgradeCost += 50;
     DamageUpgradeCount++;
     //Change text
     AllMoneyText1.moneyText.text = _playerStats.AllMoney + "$";
     DamageUpgradeText.text = DamageUpgradeCount + "/" + DamageUpgradeMax;
     DamageUpgradeCostText.text = DamageUpgradeCost + "$";
     //Save new values
     PlayerPrefs.SetFloat("DamageUpgradeCost", DamageUpgradeCost);
     PlayerPrefs.SetInt("DamageUpgradeCount", DamageUpgradeCount);
     PlayerPrefs.SetFloat("AllMoney", _playerStats.AllMoney);
 }
 public void UpgradeCritChance()
 {
     //Get the saved values
     CritChanceUpgradeCount = PlayerPrefs.GetInt("CritChanceUpgradeCount");
     CritChanceUpgradeCost = PlayerPrefs.GetFloat("CritChanceUpgradeCost");
     //Check if money too low or max upgrade count reached
     if (_playerStats.AllMoney < CritChanceUpgradeCost || CritChanceUpgradeMax <= CritChanceUpgradeCount)
         return;
     //Increase stats
     _playerStats.critChance += CritChanceUpgradeValue;
     //Subtract money
     _playerStats.AllMoney -= CritChanceUpgradeCost;
     //Increase cost and count
     CritChanceUpgradeCost += 50;
     CritChanceUpgradeCount++;
     //Change text
     AllMoneyText1.moneyText.text = _playerStats.AllMoney + "$";
     CritChanceUpgradeText.text = CritChanceUpgradeCount + "/" + CritChanceUpgradeMax;
     CritChanceUpgradeCostText.text = CritChanceUpgradeCost + "$";
     //Save new values
     PlayerPrefs.SetFloat("CritChanceUpgradeCost", CritChanceUpgradeCost);
     PlayerPrefs.SetInt("CritChanceUpgradeCount", CritChanceUpgradeCount);
     PlayerPrefs.SetFloat("AllMoney", _playerStats.AllMoney);
 }
 public void UpgradeCritMultiplier()
 {
     //Get the saved values
     CritMultiplierUpgradeCount = PlayerPrefs.GetInt("CritMultiplierUpgradeCount");
     CritMultiplierUpgradeCost = PlayerPrefs.GetFloat("CritMultiplierUpgradeCost");
     //Check if money too low or max upgrade count reached
     if (_playerStats.AllMoney < CritMultiplierUpgradeCost || CritMultiplierUpgradeMax <= CritMultiplierUpgradeCount)
         return;
     //Increase stats
     _playerStats.critDmgMultiplier += CritMultiplierUpgradeValue;
     //Subtract money
     _playerStats.AllMoney -= CritMultiplierUpgradeCost;
     //Increase cost and count
     CritMultiplierUpgradeCost += 50;
     CritMultiplierUpgradeCount++;
     //Change text
     AllMoneyText1.moneyText.text = _playerStats.AllMoney + "$";
     CritMultiplierUpgradeText.text = CritMultiplierUpgradeCount + "/" + CritMultiplierUpgradeMax;
     CritMultiplierUpgradeCostText.text = CritMultiplierUpgradeCost + "$";
     //Save new values
     PlayerPrefs.SetFloat("CritMultiplierUpgradeCost", CritMultiplierUpgradeCost);
     PlayerPrefs.SetInt("CritMultiplierUpgradeCount", CritMultiplierUpgradeCount);
     PlayerPrefs.SetFloat("AllMoney", _playerStats.AllMoney);
     
 }

}