How can I make sure that the value of "money" is saved when restarting the game?

Question

Unity

Here is the script

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Advertisements;
using UnityEngine.UI;

public class UnityAds : MonoBehaviour, IUnityAdsListener
{
    
    string placement = "rewardedVideo";
    public float money;
    public Text moneyTxt;

    void Start()
    {
        Advertisement.AddListener(this);
        Advertisement.Initialize("4037106", true);
    }


    public void OnUnityAdsDidFinish(string placementId, ShowResult showResult)
    {
        if (showResult == ShowResult.Finished)
        {
            moneyTxt.text = "Money:" + money++; 
        }
        else if (showResult == ShowResult.Failed)
        {
            //On no!
        }
    }

    public void OnUnityAdsDidStart(string placementId)
    {
    }

    public void OnUnityAdsReady(string placementId)
    {
    }

    public void OnUnityAdsDidError(string message)
    {
    }
    

    public void ShowUnityAD(string p)
    {
        Advertisement.Show(p);